diff --git a/.github/ISSUE_TEMPLATE/upstream-sync.md b/.github/ISSUE_TEMPLATE/upstream-sync.md
new file mode 100644
index 0000000..797e475
--- /dev/null
+++ b/.github/ISSUE_TEMPLATE/upstream-sync.md
@@ -0,0 +1,33 @@
+---
+name: Upstream Sync Report
+about: Auto-generated report for upstream sync
+title: '🔄 Upstream Sync: {{ date | date("YYYY-MM-DD") }}'
+labels: upstream-sync, automated
+assignees: ""
+---
+
+## 🔄 Upstream 自動同步報告
+
+**同步日期:** {{ date }}
+**新 Commits:** {{ commit_count }}
+
+### 📝 變更摘要
+
+```
+{{ commits_list }}
+```
+
+### 🐳 Docker Image
+
+- **Tag:** `upstream-{{ date_tag }}`
+- **Smoke Test:** {{ smoke_test_status }}
+
+### ⏳ 後續動作
+
+- [ ] 檢視變更內容
+- [ ] 確認 smoke test 結果
+- [ ] 決定是否 merge 到 main
+
+---
+
+_此 Issue 由 GitHub Actions 自動建立_
diff --git a/.github/UPSTREAM_SYNC.md b/.github/UPSTREAM_SYNC.md
new file mode 100644
index 0000000..d5e4bd7
--- /dev/null
+++ b/.github/UPSTREAM_SYNC.md
@@ -0,0 +1,280 @@
+# 🔄 Upstream 自動同步機制
+
+本專案實作了完整的 upstream 自動同步、變更追蹤與 smoke test 機制。
+
+## 📋 目錄
+
+- [功能概述](#功能概述)
+- [工作流程圖](#工作流程圖)
+- [Workflow 說明](#workflow-說明)
+- [Smoke Test 內容](#smoke-test-內容)
+- [設定說明](#設定說明)
+- [手動操作](#手動操作)
+
+---
+
+## 功能概述
+
+### 1️⃣ 自動同步 Upstream
+
+| 功能       | 說明                         |
+| ---------- | ---------------------------- |
+| 觸發方式   | 每 6 小時自動檢查 / 手動觸發 |
+| 同步目標   | `dev` 分支                   |
+| Merge 策略 | 自動 merge（無衝突時）       |
+| 衝突處理   | 自動建立 GitHub Issue 通知   |
+
+### 2️⃣ 變更摘要
+
+同步完成後自動產生：
+
+- ✅ GitHub Issue（詳細變更記錄）
+- ✅ `upstream-changelog.md`（累積變更歷史）
+- ✅ GitHub Actions Summary（快速查看）
+
+### 3️⃣ Smoke Test
+
+| 測試項目       | 內容                                   | 時間限制      |
+| -------------- | -------------------------------------- | ------------- |
+| Container 啟動 | 驗證 image 可正常啟動                  | 60s           |
+| 工具檢查       | libreoffice, pandoc, ffmpeg, tesseract | 30s           |
+| 最小轉換       | txt → pdf                              | 60s           |
+| API 端點       | healthcheck, root                      | 10s           |
+| **總計**       |                                        | **< 10 分鐘** |
+
+---
+
+## 工作流程圖
+
+```
+┌─────────────────────────────────────────────────────────────────────────┐
+│                         Upstream 自動同步流程                              │
+└─────────────────────────────────────────────────────────────────────────┘
+
+    ┌──────────────┐
+    │   Upstream   │
+    │  (C4illin/   │
+    │  ConvertX)   │
+    └──────┬───────┘
+           │
+           │ 每 6 小時檢查
+           ▼
+    ┌──────────────┐     無更新      ┌──────────────┐
+    │  檢查是否有   │ ─────────────► │   結束       │
+    │  新 commits  │                 └──────────────┘
+    └──────┬───────┘
+           │ 有更新
+           ▼
+    ┌──────────────┐     衝突        ┌──────────────┐
+    │  自動 Merge  │ ─────────────► │ 建立 Issue   │
+    │  到 dev 分支  │                │ 需手動處理    │
+    └──────┬───────┘                └──────────────┘
+           │ 成功
+           ▼
+    ┌──────────────┐
+    │  產生變更摘要  │
+    │  • Issue     │
+    │  • Changelog │
+    └──────┬───────┘
+           │
+           ▼
+    ┌──────────────┐
+    │  Push 到 dev │
+    └──────┬───────┘
+           │
+           │ 觸發 upstream-sync.yml
+           ▼
+    ┌──────────────┐
+    │  Build 測試  │
+    │  Image (amd64)│
+    └──────┬───────┘
+           │
+           ▼
+    ┌──────────────────────────────────────────────────┐
+    │                  Smoke Test                       │
+    │  ┌────────────┐ ┌────────────┐ ┌────────────┐   │
+    │  │ Container  │ │   工具     │ │   轉換     │   │
+    │  │   啟動     │ │   檢查     │ │   測試     │   │
+    │  └─────┬──────┘ └─────┬──────┘ └─────┬──────┘   │
+    │        │              │              │           │
+    │        └──────────────┼──────────────┘           │
+    │                       │                          │
+    └───────────────────────┼──────────────────────────┘
+                            │
+              ┌─────────────┴─────────────┐
+              │                           │
+              ▼                           ▼
+       ┌────────────┐              ┌────────────┐
+       │  ✅ 通過   │              │  ❌ 失敗   │
+       └─────┬──────┘              └─────┬──────┘
+             │                           │
+             ▼                           ▼
+       ┌────────────┐              ┌────────────┐
+       │ Build 並   │              │ Workflow   │
+       │ Push 到    │              │ 失敗       │
+       │ Docker Hub │              │ (不發布)    │
+       └─────┬──────┘              └────────────┘
+             │
+             ▼
+       ┌────────────────────────┐
+       │ upstream-YYYYMMDD tag  │
+       │ ❌ 不更新 latest        │
+       │ ❌ 不打 semver tag      │
+       └────────────────────────┘
+```
+
+---
+
+## Workflow 說明
+
+### `auto-upstream-sync.yml`
+
+**用途：** 自動檢測並同步 upstream 更新
+
+**觸發條件：**
+
+- ⏰ 每 6 小時自動執行
+- 🖱️ 手動觸發
+
+**主要步驟：**
+
+1. Fetch upstream 最新程式碼
+2. 檢查是否有新 commits
+3. 自動 merge 到 `dev` 分支
+4. 產生變更摘要（Issue + Changelog）
+5. Push 到 `dev`
+
+### `upstream-sync.yml`
+
+**用途：** 當 `dev` 分支有 push 時，執行 build + smoke test
+
+**觸發條件：**
+
+- 📦 `dev` 分支有 push
+
+**主要步驟：**
+
+1. Build 測試用 image（僅 amd64，加速測試）
+2. 執行 Smoke Test（10 分鐘內）
+3. 測試通過後 build multi-arch image
+4. Push 到 Docker Hub（tag: `upstream-YYYYMMDD`）
+
+---
+
+## Smoke Test 內容
+
+### Test 1: Container 啟動測試
+
+```bash
+# 啟動 container 並等待 healthcheck 回應
+docker run -d --name convertx-test $IMAGE
+curl http://localhost:3000/healthcheck
+```
+
+### Test 2: 關鍵工具檢查
+
+```bash
+# 必須通過（任一失敗則整體失敗）
+libreoffice --version
+pandoc --version
+ffmpeg -version
+tesseract --version
+```
+
+### Test 3: 最小轉換測試
+
+```bash
+# txt → pdf 轉換測試
+echo "test" > test.txt
+libreoffice --headless --convert-to pdf test.txt
+```
+
+### Test 4: API 端點檢查
+
+```bash
+# 確認服務正常運作
+curl http://localhost:3000/healthcheck
+curl http://localhost:3000/
+```
+
+---
+
+## 設定說明
+
+### 必要的 GitHub Secrets
+
+在 Repository Settings → Secrets and variables → Actions 中設定：
+
+| Secret 名稱          | 說明                    |
+| -------------------- | ----------------------- |
+| `DOCKERHUB_USERNAME` | Docker Hub 帳號         |
+| `DOCKERHUB_TOKEN`    | Docker Hub Access Token |
+
+### 分支保護規則
+
+建議設定：
+
+**`main` 分支：**
+
+- ✅ Require pull request before merging
+- ✅ Require status checks to pass
+- ❌ Allow force pushes
+
+**`dev` 分支：**
+
+- ✅ Allow direct pushes (for automation)
+
+---
+
+## 手動操作
+
+### 手動觸發同步
+
+1. 前往 Actions → Auto Upstream Sync
+2. 點選 "Run workflow"
+3. 可選擇「強制同步」
+
+### 手動處理 Merge 衝突
+
+當自動同步發生衝突時：
+
+```bash
+# 1. 切換到 dev 分支
+git checkout dev
+
+# 2. 添加 upstream remote（如果還沒有）
+git remote add upstream https://github.com/C4illin/ConvertX.git
+
+# 3. Fetch upstream
+git fetch upstream main
+
+# 4. Merge upstream
+git merge upstream/main
+
+# 5. 解決衝突
+# ... 編輯衝突的檔案 ...
+
+# 6. 提交並 push
+git add .
+git commit -m "Resolve merge conflicts with upstream"
+git push origin dev
+```
+
+---
+
+## ⚠️ 注意事項
+
+1. **不會自動更新 `latest` tag** - 需要手動發布正式版本
+2. **不會自動打 semver tag** - 需要手動建立 release
+3. **`main` 分支不會被自動修改** - 只有 `dev` 會自動同步
+4. **Smoke test 失敗時不會發布 image** - 確保品質
+
+---
+
+## 📊 Docker Image Tag 規則
+
+| Tag 格式            | 說明                               | 自動/手動 |
+| ------------------- | ---------------------------------- | --------- |
+| `upstream-YYYYMMDD` | Upstream 同步版（經過 smoke test） | 自動      |
+| `vX.Y.Z`            | 正式版本                           | 手動      |
+| `latest`            | 最新穩定版                         | 手動      |
diff --git a/.github/scripts/smoke-test.sh b/.github/scripts/smoke-test.sh
new file mode 100644
index 0000000..1763d2b
--- /dev/null
+++ b/.github/scripts/smoke-test.sh
@@ -0,0 +1,238 @@
+#!/bin/bash
+# ==============================================================================
+# ConvertX Smoke Test Script
+# 用於驗證 Docker image 的基本功能
+# ==============================================================================
+
+set -e
+
+CONTAINER_NAME="${CONTAINER_NAME:-convertx-test}"
+TEST_TIMEOUT="${TEST_TIMEOUT:-60}"
+
+echo "=================================================="
+echo "🧪 ConvertX Smoke Test"
+echo "=================================================="
+echo ""
+
+# 顏色定義
+RED='\033[0;31m'
+GREEN='\033[0;32m'
+YELLOW='\033[1;33m'
+NC='\033[0m' # No Color
+
+pass() {
+    echo -e "${GREEN}✅ PASS${NC}: $1"
+}
+
+fail() {
+    echo -e "${RED}❌ FAIL${NC}: $1"
+    exit 1
+}
+
+warn() {
+    echo -e "${YELLOW}⚠️ WARN${NC}: $1"
+}
+
+# ==============================================================================
+# Test 1: Container 啟動測試
+# ==============================================================================
+test_container_startup() {
+    echo ""
+    echo "📦 Test 1: Container Startup"
+    echo "----------------------------"
+    
+    echo "Waiting for container to be healthy..."
+    
+    for i in $(seq 1 $TEST_TIMEOUT); do
+        if docker exec $CONTAINER_NAME curl -sf http://localhost:3000/healthcheck > /dev/null 2>&1; then
+            pass "Container started in ${i}s"
+            return 0
+        fi
+        sleep 1
+    done
+    
+    fail "Container failed to start within ${TEST_TIMEOUT}s"
+}
+
+# ==============================================================================
+# Test 2: 關鍵工具存在性檢查
+# ==============================================================================
+test_critical_tools() {
+    echo ""
+    echo "🔧 Test 2: Critical Tools Availability"
+    echo "---------------------------------------"
+    
+    local failed=0
+    
+    # LibreOffice (必要)
+    echo -n "  libreoffice: "
+    if docker exec $CONTAINER_NAME libreoffice --version > /dev/null 2>&1; then
+        VERSION=$(docker exec $CONTAINER_NAME libreoffice --version 2>/dev/null | head -1)
+        echo -e "${GREEN}OK${NC} ($VERSION)"
+    else
+        echo -e "${RED}MISSING${NC}"
+        failed=1
+    fi
+    
+    # Pandoc (必要)
+    echo -n "  pandoc: "
+    if docker exec $CONTAINER_NAME pandoc --version > /dev/null 2>&1; then
+        VERSION=$(docker exec $CONTAINER_NAME pandoc --version 2>/dev/null | head -1)
+        echo -e "${GREEN}OK${NC} ($VERSION)"
+    else
+        echo -e "${RED}MISSING${NC}"
+        failed=1
+    fi
+    
+    # FFmpeg (必要)
+    echo -n "  ffmpeg: "
+    if docker exec $CONTAINER_NAME ffmpeg -version > /dev/null 2>&1; then
+        VERSION=$(docker exec $CONTAINER_NAME ffmpeg -version 2>/dev/null | head -1 | awk '{print $3}')
+        echo -e "${GREEN}OK${NC} (v$VERSION)"
+    else
+        echo -e "${RED}MISSING${NC}"
+        failed=1
+    fi
+    
+    # Tesseract (必要)
+    echo -n "  tesseract: "
+    if docker exec $CONTAINER_NAME tesseract --version > /dev/null 2>&1; then
+        VERSION=$(docker exec $CONTAINER_NAME tesseract --version 2>/dev/null | head -1)
+        echo -e "${GREEN}OK${NC} ($VERSION)"
+    else
+        echo -e "${RED}MISSING${NC}"
+        failed=1
+    fi
+    
+    echo ""
+    echo "  Additional tools (optional):"
+    
+    # ImageMagick
+    echo -n "  imagemagick: "
+    if docker exec $CONTAINER_NAME magick -version > /dev/null 2>&1; then
+        echo -e "${GREEN}OK${NC}"
+    else
+        echo -e "${YELLOW}Not found${NC}"
+    fi
+    
+    # Inkscape
+    echo -n "  inkscape: "
+    if docker exec $CONTAINER_NAME inkscape --version > /dev/null 2>&1; then
+        echo -e "${GREEN}OK${NC}"
+    else
+        echo -e "${YELLOW}Not found${NC}"
+    fi
+    
+    # GraphicsMagick
+    echo -n "  graphicsmagick: "
+    if docker exec $CONTAINER_NAME gm version > /dev/null 2>&1; then
+        echo -e "${GREEN}OK${NC}"
+    else
+        echo -e "${YELLOW}Not found${NC}"
+    fi
+    
+    # Calibre
+    echo -n "  calibre: "
+    if docker exec $CONTAINER_NAME ebook-convert --version > /dev/null 2>&1; then
+        echo -e "${GREEN}OK${NC}"
+    else
+        echo -e "${YELLOW}Not found${NC}"
+    fi
+    
+    echo ""
+    
+    if [ $failed -eq 1 ]; then
+        fail "Critical tools check failed"
+    else
+        pass "All critical tools available"
+    fi
+}
+
+# ==============================================================================
+# Test 3: 最小轉換測試
+# ==============================================================================
+test_minimal_conversion() {
+    echo ""
+    echo "📄 Test 3: Minimal Conversion"
+    echo "-----------------------------"
+    
+    # 在 container 內建立測試檔案並轉換
+    echo "  Creating test file..."
+    docker exec $CONTAINER_NAME sh -c "echo 'ConvertX Smoke Test - $(date)' > /tmp/test.txt"
+    
+    echo "  Converting txt → pdf using LibreOffice..."
+    if docker exec $CONTAINER_NAME sh -c "cd /tmp && libreoffice --headless --convert-to pdf test.txt" > /dev/null 2>&1; then
+        # 檢查輸出檔案
+        if docker exec $CONTAINER_NAME test -f /tmp/test.pdf; then
+            SIZE=$(docker exec $CONTAINER_NAME stat -c%s /tmp/test.pdf 2>/dev/null || echo "unknown")
+            pass "Conversion successful (output: ${SIZE} bytes)"
+        else
+            fail "Conversion failed - output file not found"
+        fi
+    else
+        fail "LibreOffice conversion command failed"
+    fi
+    
+    # 清理
+    docker exec $CONTAINER_NAME rm -f /tmp/test.txt /tmp/test.pdf 2>/dev/null || true
+}
+
+# ==============================================================================
+# Test 4: API 端點檢查
+# ==============================================================================
+test_api_endpoints() {
+    echo ""
+    echo "🌐 Test 4: API Endpoints"
+    echo "------------------------"
+    
+    local failed=0
+    
+    # Healthcheck
+    echo -n "  GET /healthcheck: "
+    if docker exec $CONTAINER_NAME curl -sf http://localhost:3000/healthcheck > /dev/null 2>&1; then
+        echo -e "${GREEN}200 OK${NC}"
+    else
+        echo -e "${RED}FAILED${NC}"
+        failed=1
+    fi
+    
+    # Root
+    echo -n "  GET /: "
+    if docker exec $CONTAINER_NAME curl -sf http://localhost:3000/ > /dev/null 2>&1; then
+        echo -e "${GREEN}200 OK${NC}"
+    else
+        echo -e "${RED}FAILED${NC}"
+        failed=1
+    fi
+    
+    echo ""
+    
+    if [ $failed -eq 1 ]; then
+        fail "API endpoints check failed"
+    else
+        pass "All API endpoints responding"
+    fi
+}
+
+# ==============================================================================
+# Main
+# ==============================================================================
+main() {
+    local start_time=$(date +%s)
+    
+    test_container_startup
+    test_critical_tools
+    test_minimal_conversion
+    test_api_endpoints
+    
+    local end_time=$(date +%s)
+    local duration=$((end_time - start_time))
+    
+    echo ""
+    echo "=================================================="
+    echo -e "🎉 ${GREEN}All smoke tests passed!${NC}"
+    echo "   Total time: ${duration}s"
+    echo "=================================================="
+}
+
+main "$@"
diff --git a/.github/test-files/test.txt b/.github/test-files/test.txt
new file mode 100644
index 0000000..8f9696f
--- /dev/null
+++ b/.github/test-files/test.txt
@@ -0,0 +1,6 @@
+Hello, this is a smoke test file for ConvertX.
+這是 ConvertX 的冒煙測試檔案。
+日本語テスト：こんにちは
+한국어 테스트: 안녕하세요
+
+This file should be less than 1KB for quick testing.
diff --git a/.github/workflows/auto-upstream-sync.yml b/.github/workflows/auto-upstream-sync.yml
new file mode 100644
index 0000000..1716491
--- /dev/null
+++ b/.github/workflows/auto-upstream-sync.yml
@@ -0,0 +1,281 @@
+# ==============================================================================
+# 自動同步 Upstream Repository
+# 功能：
+#   1. 定時檢查 upstream 更新
+#   2. 自動 merge 到 dev 分支
+#   3. 產生變更摘要（Change Summary）
+#   4. 觸發後續的 build + smoke test
+# ==============================================================================
+
+name: Auto Upstream Sync
+
+on:
+  # 每 6 小時檢查一次 upstream
+  schedule:
+    - cron: "0 */6 * * *"
+  # 手動觸發
+  workflow_dispatch:
+    inputs:
+      force_sync:
+        description: "強制同步（即使無新 commit）"
+        type: boolean
+        default: false
+
+env:
+  UPSTREAM_REPO: https://github.com/C4illin/ConvertX.git
+  TARGET_BRANCH: dev
+  UPSTREAM_BRANCH: main
+
+permissions:
+  contents: write
+  issues: write
+
+jobs:
+  check-and-sync:
+    name: Check & Sync Upstream
+    runs-on: ubuntu-latest
+    outputs:
+      has_updates: ${{ steps.check.outputs.has_updates }}
+      new_commits: ${{ steps.check.outputs.new_commits }}
+      commit_count: ${{ steps.check.outputs.commit_count }}
+      sync_date: ${{ steps.date.outputs.date }}
+      changelog: ${{ steps.changelog.outputs.changelog }}
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+        with:
+          ref: ${{ env.TARGET_BRANCH }}
+          fetch-depth: 0
+          token: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Get current date
+        id: date
+        run: echo "date=$(date +'%Y%m%d')" >> $GITHUB_OUTPUT
+
+      - name: Configure Git
+        run: |
+          git config user.name "github-actions[bot]"
+          git config user.email "github-actions[bot]@users.noreply.github.com"
+
+      - name: Add upstream remote
+        run: |
+          git remote add upstream ${{ env.UPSTREAM_REPO }} || true
+          git fetch upstream ${{ env.UPSTREAM_BRANCH }}
+
+      - name: Check for upstream updates
+        id: check
+        run: |
+          # 取得本地 dev 分支的最後一次 upstream merge commit
+          # 我們用 upstream/main 與目前 HEAD 比較
+
+          LOCAL_HEAD=$(git rev-parse HEAD)
+          UPSTREAM_HEAD=$(git rev-parse upstream/${{ env.UPSTREAM_BRANCH }})
+
+          echo "Local HEAD: $LOCAL_HEAD"
+          echo "Upstream HEAD: $UPSTREAM_HEAD"
+
+          # 檢查 upstream 是否有新的 commits
+          MERGE_BASE=$(git merge-base HEAD upstream/${{ env.UPSTREAM_BRANCH }})
+          echo "Merge base: $MERGE_BASE"
+
+          if [ "$MERGE_BASE" = "$UPSTREAM_HEAD" ]; then
+            echo "✅ Already up to date with upstream"
+            echo "has_updates=false" >> $GITHUB_OUTPUT
+            echo "commit_count=0" >> $GITHUB_OUTPUT
+          else
+            # 計算新的 commits 數量
+            NEW_COMMITS=$(git rev-list --count $MERGE_BASE..$UPSTREAM_HEAD)
+            echo "🔄 Found $NEW_COMMITS new commits from upstream"
+            echo "has_updates=true" >> $GITHUB_OUTPUT
+            echo "commit_count=$NEW_COMMITS" >> $GITHUB_OUTPUT
+            
+            # 取得新 commits 的列表
+            COMMITS_LIST=$(git log --oneline $MERGE_BASE..$UPSTREAM_HEAD)
+            echo "new_commits<<EOF" >> $GITHUB_OUTPUT
+            echo "$COMMITS_LIST" >> $GITHUB_OUTPUT
+            echo "EOF" >> $GITHUB_OUTPUT
+          fi
+
+      - name: Generate changelog before merge
+        id: changelog
+        if: steps.check.outputs.has_updates == 'true' || github.event.inputs.force_sync == 'true'
+        run: |
+          MERGE_BASE=$(git merge-base HEAD upstream/${{ env.UPSTREAM_BRANCH }})
+
+          echo "## 📋 Upstream 變更摘要" > changelog.md
+          echo "" >> changelog.md
+          echo "**同步時間:** $(date +'%Y-%m-%d %H:%M:%S UTC')" >> changelog.md
+          echo "**Upstream 分支:** ${{ env.UPSTREAM_BRANCH }}" >> changelog.md
+          echo "**新 Commits 數量:** ${{ steps.check.outputs.commit_count }}" >> changelog.md
+          echo "" >> changelog.md
+
+          echo "### 📝 Commit 列表" >> changelog.md
+          echo "" >> changelog.md
+          echo "\`\`\`" >> changelog.md
+          git log --oneline --no-merges $MERGE_BASE..upstream/${{ env.UPSTREAM_BRANCH }} >> changelog.md
+          echo "\`\`\`" >> changelog.md
+          echo "" >> changelog.md
+
+          echo "### 📊 變更統計" >> changelog.md
+          echo "" >> changelog.md
+          echo "\`\`\`" >> changelog.md
+          git diff --stat $MERGE_BASE..upstream/${{ env.UPSTREAM_BRANCH }} >> changelog.md
+          echo "\`\`\`" >> changelog.md
+          echo "" >> changelog.md
+
+          echo "### 🔍 變更的檔案" >> changelog.md
+          echo "" >> changelog.md
+          git diff --name-status $MERGE_BASE..upstream/${{ env.UPSTREAM_BRANCH }} | while read line; do
+            STATUS=$(echo "$line" | awk '{print $1}')
+            FILE=$(echo "$line" | awk '{print $2}')
+            case $STATUS in
+              A) echo "- ✅ **新增** \`$FILE\`" >> changelog.md ;;
+              M) echo "- ✏️ **修改** \`$FILE\`" >> changelog.md ;;
+              D) echo "- ❌ **刪除** \`$FILE\`" >> changelog.md ;;
+              R*) echo "- 🔄 **重新命名** \`$FILE\`" >> changelog.md ;;
+              *) echo "- 📄 \`$FILE\` ($STATUS)" >> changelog.md ;;
+            esac
+          done
+
+          cat changelog.md
+
+          # 輸出給後續步驟使用
+          CHANGELOG_CONTENT=$(cat changelog.md)
+          echo "changelog<<EOF" >> $GITHUB_OUTPUT
+          echo "$CHANGELOG_CONTENT" >> $GITHUB_OUTPUT
+          echo "EOF" >> $GITHUB_OUTPUT
+
+      - name: Merge upstream changes
+        id: merge
+        if: steps.check.outputs.has_updates == 'true' || github.event.inputs.force_sync == 'true'
+        run: |
+          echo "🔄 Merging upstream/${{ env.UPSTREAM_BRANCH }} into ${{ env.TARGET_BRANCH }}..."
+
+          # 嘗試自動 merge
+          if git merge upstream/${{ env.UPSTREAM_BRANCH }} --no-edit -m "🔄 Auto-merge upstream changes ($(date +'%Y-%m-%d'))"; then
+            echo "✅ Merge successful!"
+            echo "merge_success=true" >> $GITHUB_OUTPUT
+          else
+            echo "❌ Merge conflict detected!"
+            echo "merge_success=false" >> $GITHUB_OUTPUT
+            
+            # 取消 merge
+            git merge --abort
+            
+            # 建立 conflict issue
+            exit 1
+          fi
+
+      - name: Push changes
+        if: steps.merge.outputs.merge_success == 'true'
+        run: |
+          git push origin ${{ env.TARGET_BRANCH }}
+          echo "✅ Changes pushed to ${{ env.TARGET_BRANCH }}"
+
+      - name: Commit changelog
+        if: steps.merge.outputs.merge_success == 'true'
+        run: |
+          # 更新 upstream-changelog.md
+          if [ -f upstream-changelog.md ]; then
+            # 在檔案開頭插入新的 changelog
+            echo "" >> changelog.md
+            echo "---" >> changelog.md
+            echo "" >> changelog.md
+            cat upstream-changelog.md >> changelog.md
+          fi
+
+          mv changelog.md upstream-changelog.md
+          git add upstream-changelog.md
+          git commit -m "📋 Update upstream changelog (${{ steps.date.outputs.date }})" || true
+          git push origin ${{ env.TARGET_BRANCH }} || true
+
+      - name: Create GitHub Issue for sync summary
+        if: steps.merge.outputs.merge_success == 'true' && steps.check.outputs.commit_count > 0
+        uses: actions/github-script@v7
+        with:
+          script: |
+            const date = '${{ steps.date.outputs.date }}';
+            const commitCount = '${{ steps.check.outputs.commit_count }}';
+
+            const body = `## 🔄 Upstream 自動同步完成
+
+            **同步日期:** ${date}
+            **新 Commits:** ${commitCount} 個
+            **目標分支:** \`dev\`
+
+            ### 📝 變更摘要
+
+            \`\`\`
+            ${{ steps.check.outputs.new_commits }}
+            \`\`\`
+
+            ### ⏳ 後續動作
+
+            - [ ] Smoke test 執行中...
+            - [ ] Docker image 建構中 (\`upstream-${date}\`)
+
+            ---
+            *此 Issue 由 GitHub Actions 自動建立*
+            `;
+
+            await github.rest.issues.create({
+              owner: context.repo.owner,
+              repo: context.repo.repo,
+              title: `🔄 Upstream Sync: ${date} (${commitCount} commits)`,
+              body: body,
+              labels: ['upstream-sync', 'automated']
+            });
+
+      - name: Create Issue for merge conflict
+        if: failure() && steps.merge.outputs.merge_success == 'false'
+        uses: actions/github-script@v7
+        with:
+          script: |
+            const date = '${{ steps.date.outputs.date }}';
+
+            await github.rest.issues.create({
+              owner: context.repo.owner,
+              repo: context.repo.repo,
+              title: `⚠️ Upstream Sync 衝突: ${date}`,
+              body: `## ⚠️ Upstream 同步發生衝突
+              
+              需要手動解決 merge conflict。
+              
+              ### 處理步驟
+              
+              \`\`\`bash
+              git fetch upstream main
+              git checkout dev
+              git merge upstream/main
+              # 解決衝突後
+              git add .
+              git commit
+              git push origin dev
+              \`\`\`
+              
+              ---
+              *此 Issue 由 GitHub Actions 自動建立*
+              `,
+              labels: ['upstream-sync', 'merge-conflict', 'needs-attention']
+            });
+
+      - name: Summary
+        if: always()
+        run: |
+          echo "## 🔄 Upstream Sync Summary" >> $GITHUB_STEP_SUMMARY
+          echo "" >> $GITHUB_STEP_SUMMARY
+          echo "| 項目 | 狀態 |" >> $GITHUB_STEP_SUMMARY
+          echo "|------|------|" >> $GITHUB_STEP_SUMMARY
+          echo "| 檢查時間 | $(date +'%Y-%m-%d %H:%M:%S UTC') |" >> $GITHUB_STEP_SUMMARY
+          echo "| 有新更新 | ${{ steps.check.outputs.has_updates }} |" >> $GITHUB_STEP_SUMMARY
+          echo "| 新 Commits | ${{ steps.check.outputs.commit_count }} |" >> $GITHUB_STEP_SUMMARY
+          echo "| Merge 成功 | ${{ steps.merge.outputs.merge_success || 'N/A' }} |" >> $GITHUB_STEP_SUMMARY
+          echo "" >> $GITHUB_STEP_SUMMARY
+
+          if [ "${{ steps.check.outputs.has_updates }}" == "true" ]; then
+            echo "### 📝 New Commits" >> $GITHUB_STEP_SUMMARY
+            echo "\`\`\`" >> $GITHUB_STEP_SUMMARY
+            echo "${{ steps.check.outputs.new_commits }}" >> $GITHUB_STEP_SUMMARY
+            echo "\`\`\`" >> $GITHUB_STEP_SUMMARY
+          fi
diff --git a/.github/workflows/upstream-sync.yml b/.github/workflows/upstream-sync.yml
index e1db9c9..350e4b2 100644
--- a/.github/workflows/upstream-sync.yml
+++ b/.github/workflows/upstream-sync.yml
@@ -1,3 +1,12 @@
+# ==============================================================================
+# Upstream Sync Build + Smoke Test
+# 功能：
+#   1. dev 分支有 push 時自動觸發
+#   2. 建構 Docker image（僅 amd64 用於測試）
+#   3. 執行 smoke test（10 分鐘內完成）
+#   4. 測試通過後推送 multi-arch image
+# ==============================================================================
+
 name: Upstream Sync Build
 
 on:
@@ -7,15 +16,56 @@ on:
 
 env:
   DOCKER_IMAGE: convertx/convertx-cn
+  TEST_IMAGE: convertx-cn-test
+  # Smoke test 超時時間（秒）
+  SMOKE_TEST_TIMEOUT: 600
+
+concurrency:
+  group: upstream-sync-${{ github.ref }}
+  cancel-in-progress: true
 
 jobs:
-  build-and-push:
+  # ==========================================================================
+  # Job 1: 快速建構測試用 image（僅 amd64）
+  # ==========================================================================
+  build-test-image:
+    name: Build Test Image
     runs-on: ubuntu-latest
-    
+    outputs:
+      image_tag: ${{ steps.date.outputs.date }}
+
     steps:
       - name: Checkout repository
         uses: actions/checkout@v4
 
+      # ========================================
+      # 清理磁碟空間（解決 no space left on device）
+      # ========================================
+      - name: Free disk space
+        run: |
+          echo "🧹 Cleaning up disk space..."
+          echo "Before cleanup:"
+          df -h
+
+          # 移除不需要的預裝軟體
+          sudo rm -rf /usr/share/dotnet
+          sudo rm -rf /usr/local/lib/android
+          sudo rm -rf /opt/ghc
+          sudo rm -rf /opt/hostedtoolcache/CodeQL
+          sudo rm -rf /usr/local/share/boost
+          sudo rm -rf /usr/share/swift
+
+          # 清理 apt cache
+          sudo apt-get clean
+          sudo apt-get autoremove -y
+
+          # 清理 Docker 舊資料
+          docker system prune -af --volumes || true
+
+          echo ""
+          echo "After cleanup:"
+          df -h
+
       - name: Get current date
         id: date
         run: echo "date=$(date +'%Y%m%d')" >> $GITHUB_OUTPUT
@@ -23,6 +73,308 @@ jobs:
       - name: Set up Docker Buildx
         uses: docker/setup-buildx-action@v3
 
+      - name: Build test image (amd64 only)
+        uses: docker/build-push-action@v6
+        with:
+          context: .
+          push: false
+          load: true
+          tags: ${{ env.TEST_IMAGE }}:test
+          platforms: linux/amd64
+          cache-from: type=gha
+          cache-to: type=gha,mode=max
+
+      - name: Save Docker image
+        run: |
+          docker save ${{ env.TEST_IMAGE }}:test -o /tmp/test-image.tar
+
+      - name: Upload test image
+        uses: actions/upload-artifact@v4
+        with:
+          name: test-image
+          path: /tmp/test-image.tar
+          retention-days: 1
+
+  # ==========================================================================
+  # Job 2: Smoke Test（必須在 10 分鐘內完成）
+  # ==========================================================================
+  smoke-test:
+    name: Smoke Test
+    runs-on: ubuntu-latest
+    needs: build-test-image
+    timeout-minutes: 10
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Download test image
+        uses: actions/download-artifact@v4
+        with:
+          name: test-image
+          path: /tmp
+
+      - name: Load Docker image
+        run: |
+          docker load -i /tmp/test-image.tar
+
+      - name: Create test files
+        run: |
+          mkdir -p /tmp/smoke-test
+
+          # 建立極小的測試檔案 (<1KB)
+          echo "Hello, ConvertX Smoke Test!" > /tmp/smoke-test/test.txt
+          echo "這是中文測試檔案" >> /tmp/smoke-test/test.txt
+
+      # ========================================
+      # Test 1: Container 啟動測試
+      # ========================================
+      - name: "Test 1: Container startup"
+        id: test_startup
+        run: |
+          echo "🚀 Testing container startup..."
+
+          # 啟動 container（背景執行）
+          docker run -d \
+            --name convertx-test \
+            -p 3000:3000 \
+            -v /tmp/smoke-test:/data \
+            -e DATA_DIR=/data \
+            ${{ env.TEST_IMAGE }}:test
+
+          # 等待啟動（最多 60 秒）
+          echo "⏳ Waiting for container to start..."
+          for i in {1..60}; do
+            if docker exec convertx-test curl -sf http://localhost:3000/healthcheck > /dev/null 2>&1; then
+              echo "✅ Container started successfully in ${i}s"
+              echo "startup_time=${i}" >> $GITHUB_OUTPUT
+              exit 0
+            fi
+            sleep 1
+          done
+
+          echo "❌ Container failed to start within 60s"
+          docker logs convertx-test
+          exit 1
+
+      # ========================================
+      # Test 2: 關鍵工具存在性檢查
+      # ========================================
+      - name: "Test 2: Tool availability check"
+        id: test_tools
+        run: |
+          echo "🔧 Checking critical tools..."
+
+          FAILED=0
+
+          # LibreOffice
+          echo -n "  libreoffice: "
+          if docker exec convertx-test libreoffice --version 2>/dev/null; then
+            echo "✅"
+          else
+            echo "❌ FAILED"
+            FAILED=1
+          fi
+
+          # Pandoc
+          echo -n "  pandoc: "
+          if docker exec convertx-test pandoc --version 2>/dev/null | head -1; then
+            echo "✅"
+          else
+            echo "❌ FAILED"
+            FAILED=1
+          fi
+
+          # FFmpeg
+          echo -n "  ffmpeg: "
+          if docker exec convertx-test ffmpeg -version 2>/dev/null | head -1; then
+            echo "✅"
+          else
+            echo "❌ FAILED"
+            FAILED=1
+          fi
+
+          # Tesseract
+          echo -n "  tesseract: "
+          if docker exec convertx-test tesseract --version 2>/dev/null | head -1; then
+            echo "✅"
+          else
+            echo "❌ FAILED"
+            FAILED=1
+          fi
+
+          # 額外檢查更多工具
+          echo ""
+          echo "🔧 Checking additional tools..."
+
+          # ImageMagick
+          echo -n "  imagemagick: "
+          if docker exec convertx-test magick -version 2>/dev/null | head -1; then
+            echo "✅"
+          else
+            echo "⚠️ Warning (optional)"
+          fi
+
+          # Inkscape
+          echo -n "  inkscape: "
+          if docker exec convertx-test inkscape --version 2>/dev/null; then
+            echo "✅"
+          else
+            echo "⚠️ Warning (optional)"
+          fi
+
+          if [ $FAILED -eq 1 ]; then
+            echo ""
+            echo "❌ Critical tool check failed!"
+            exit 1
+          fi
+
+          echo ""
+          echo "✅ All critical tools available"
+
+      # ========================================
+      # Test 3: 最小轉換測試 (txt → pdf)
+      # ========================================
+      - name: "Test 3: Minimal conversion test"
+        id: test_conversion
+        run: |
+          echo "📄 Testing minimal conversion (txt → pdf)..."
+
+          # 使用 API 進行轉換測試
+          # 先上傳檔案
+          echo "  Uploading test file..."
+          UPLOAD_RESPONSE=$(curl -sf -X POST \
+            -F "file=@/tmp/smoke-test/test.txt" \
+            http://localhost:3000/upload 2>&1) || {
+            echo "❌ Upload failed"
+            echo "Response: $UPLOAD_RESPONSE"
+            exit 1
+          }
+
+          echo "  Upload response: $UPLOAD_RESPONSE"
+
+          # 檢查 healthcheck 確認服務正常
+          echo "  Checking service health..."
+          HEALTH=$(curl -sf http://localhost:3000/healthcheck)
+          echo "  Health: $HEALTH"
+
+          # 使用 LibreOffice 直接測試轉換能力
+          echo "  Testing LibreOffice conversion capability..."
+          docker exec convertx-test sh -c "
+            cd /tmp && \
+            echo 'Test document for smoke test' > test.txt && \
+            libreoffice --headless --convert-to pdf test.txt && \
+            ls -la test.pdf
+          " && echo "✅ Conversion test passed" || {
+            echo "❌ Conversion test failed"
+            exit 1
+          }
+
+      # ========================================
+      # Test 4: API 端點檢查
+      # ========================================
+      - name: "Test 4: API endpoints check"
+        run: |
+          echo "🌐 Checking API endpoints..."
+
+          # Healthcheck
+          echo -n "  /healthcheck: "
+          if curl -sf http://localhost:3000/healthcheck > /dev/null; then
+            echo "✅"
+          else
+            echo "❌"
+            exit 1
+          fi
+
+          # Root page
+          echo -n "  / (root): "
+          if curl -sf http://localhost:3000/ > /dev/null; then
+            echo "✅"
+          else
+            echo "❌"
+            exit 1
+          fi
+
+          # Converters list
+          echo -n "  /converters: "
+          if curl -sf http://localhost:3000/converters > /dev/null; then
+            echo "✅"
+          else
+            echo "⚠️ (may require auth)"
+          fi
+
+          echo ""
+          echo "✅ API endpoints check passed"
+
+      - name: Cleanup test container
+        if: always()
+        run: |
+          docker stop convertx-test || true
+          docker rm convertx-test || true
+
+      - name: Smoke test summary
+        if: always()
+        run: |
+          echo "## 🧪 Smoke Test Results" >> $GITHUB_STEP_SUMMARY
+          echo "" >> $GITHUB_STEP_SUMMARY
+          echo "| 測試項目 | 狀態 |" >> $GITHUB_STEP_SUMMARY
+          echo "|----------|------|" >> $GITHUB_STEP_SUMMARY
+          echo "| Container 啟動 | ✅ 通過 (${startup_time:-N/A}s) |" >> $GITHUB_STEP_SUMMARY
+          echo "| 工具檢查 (libreoffice, pandoc, ffmpeg, tesseract) | ✅ 通過 |" >> $GITHUB_STEP_SUMMARY
+          echo "| 最小轉換測試 | ✅ 通過 |" >> $GITHUB_STEP_SUMMARY
+          echo "| API 端點檢查 | ✅ 通過 |" >> $GITHUB_STEP_SUMMARY
+
+  # ==========================================================================
+  # Job 3: 測試通過後，建構並推送 multi-arch image
+  # ==========================================================================
+  build-and-push:
+    name: Build & Push Multi-arch Image
+    runs-on: ubuntu-latest
+    needs: [build-test-image, smoke-test]
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      # ========================================
+      # 清理磁碟空間（multi-arch build 需要更多空間）
+      # ========================================
+      - name: Free disk space
+        run: |
+          echo "🧹 Cleaning up disk space for multi-arch build..."
+          echo "Before cleanup:"
+          df -h
+
+          # 移除不需要的預裝軟體
+          sudo rm -rf /usr/share/dotnet
+          sudo rm -rf /usr/local/lib/android
+          sudo rm -rf /opt/ghc
+          sudo rm -rf /opt/hostedtoolcache/CodeQL
+          sudo rm -rf /usr/local/share/boost
+          sudo rm -rf /usr/share/swift
+          sudo rm -rf /opt/hostedtoolcache
+
+          # 清理 apt cache
+          sudo apt-get clean
+          sudo apt-get autoremove -y
+
+          # 清理 Docker 舊資料
+          docker system prune -af --volumes || true
+
+          echo ""
+          echo "After cleanup:"
+          df -h
+
+      - name: Get current date
+        id: date
+        run: echo "date=$(date +'%Y%m%d')" >> $GITHUB_OUTPUT
+
+      - name: Set up QEMU
+        uses: docker/setup-qemu-action@v3
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
+
       - name: Login to Docker Hub
         uses: docker/login-action@v3
         with:
@@ -45,4 +397,16 @@ jobs:
           echo "" >> $GITHUB_STEP_SUMMARY
           echo "**Image:** \`${{ env.DOCKER_IMAGE }}:upstream-${{ steps.date.outputs.date }}\`" >> $GITHUB_STEP_SUMMARY
           echo "" >> $GITHUB_STEP_SUMMARY
-          echo "This is an upstream sync build. Use version tags for stable releases." >> $GITHUB_STEP_SUMMARY
+          echo "### ✅ Smoke Test 已通過" >> $GITHUB_STEP_SUMMARY
+          echo "" >> $GITHUB_STEP_SUMMARY
+          echo "| 測試項目 | 狀態 |" >> $GITHUB_STEP_SUMMARY
+          echo "|----------|------|" >> $GITHUB_STEP_SUMMARY
+          echo "| Container 啟動 | ✅ |" >> $GITHUB_STEP_SUMMARY
+          echo "| 工具存在性檢查 | ✅ |" >> $GITHUB_STEP_SUMMARY
+          echo "| 最小轉換測試 | ✅ |" >> $GITHUB_STEP_SUMMARY
+          echo "| API 端點檢查 | ✅ |" >> $GITHUB_STEP_SUMMARY
+          echo "" >> $GITHUB_STEP_SUMMARY
+          echo "---" >> $GITHUB_STEP_SUMMARY
+          echo "⚠️ 這是 upstream 同步版本。請使用 version tags 取得穩定版本。" >> $GITHUB_STEP_SUMMARY
+          echo "" >> $GITHUB_STEP_SUMMARY
+          echo "❌ **不會更新 \`latest\` tag**" >> $GITHUB_STEP_SUMMARY