fix: ENOENT download error for archive-only converters (PDFMathTranslate/MinerU)

- Add existsSync checks in download.tsx before file access
- Fix normalizeFiletype.ts: md-t/md-i return original format (not tar.gz)
- Add outputMode: 'archive' support in main.ts with auto .tar suffix
- PDFMathTranslate outputs translated-<lang>.pdf + bilingual-<lang>.pdf (no original)
- MinerU outputs complete folder in .tar with logging
- Hide preview icon for .tar files in results.tsx
- Update Bun version: 1.2.2 -> 1.3.6
- Add Step 19: auto-deploy to remote server after Docker push

All 159 tests pass.

src/pages/download.tsx

@@ -1,3 +1,4 @@
+import { existsSync } from "node:fs";
 import { Elysia } from "elysia";
 import sanitize from "sanitize-filename";
 import { outputDir } from "..";
@@ -10,7 +11,7 @@ export const download = new Elysia()
   .use(userService)
   .get(
     "/download/:userId/:jobId/:fileName",
-    async ({ params, redirect, user }) => {
+    async ({ params, redirect, set, user }) => {
       const userId = user.id;
       const job = await db
         .query("SELECT * FROM jobs WHERE user_id = ? AND id = ?")
@@ -24,6 +25,14 @@ export const download = new Elysia()
       const fileName = sanitize(decodeURIComponent(params.fileName));
 
       const filePath = `${outputDir}${userId}/${jobId}/${fileName}`;
+      
+      // 檢查檔案是否存在
+      if (!existsSync(filePath)) {
+        console.error(`[Download] File not found: ${filePath}`);
+        set.status = 404;
+        return { error: "File not found", path: filePath };
+      }
+      
       return Bun.file(filePath);
     },
     {
@@ -32,7 +41,7 @@ export const download = new Elysia()
   )
   .get(
     "/archive/:jobId",
-    async ({ params, redirect, user }) => {
+    async ({ params, redirect, set, user }) => {
       const userId = user.id;
       const job = await db
         .query("SELECT * FROM jobs WHERE user_id = ? AND id = ?")
@@ -45,9 +54,23 @@ export const download = new Elysia()
       const jobId = decodeURIComponent(params.jobId);
       const outputPath = `${outputDir}${userId}/${jobId}`;
 
+      // 檢查輸出目錄是否存在
+      if (!existsSync(outputPath)) {
+        console.error(`[Archive] Output directory not found: ${outputPath}`);
+        set.status = 404;
+        return { error: "Output directory not found", path: outputPath };
+      }
+
       // 使用統一的封裝管理器建立 .tar（不壓縮）
       const outputTar = await createJobArchive(outputPath, jobId);
 
+      // 檢查 archive 是否成功建立
+      if (!existsSync(outputTar)) {
+        console.error(`[Archive] Failed to create archive: ${outputTar}`);
+        set.status = 500;
+        return { error: "Failed to create archive", path: outputTar };
+      }
+
       return Bun.file(outputTar);
     },
     {