feat(api): implement OpenAPI/REST API for file conversions

- Add comprehensive REST API at /api/v1 with modular structure
- Implement authentication endpoints (register, login, logout, me)
- Add converter listing and format discovery endpoints
- Create job management and file download endpoints
- Add health check endpoint for monitoring
- Set up CORS support for browser-based API clients
- Create API middleware for JWT authentication
- Add environment variables for API configuration
- Include comprehensive API documentation and test script

Infrastructure:
- Enhanced CI/CD workflow for custom Docker registries
- Docker Compose setup with dev, prod, and monitoring profiles
- Claude.ai integration files for development workflow
- Environment-based configuration with .env.development

Known limitations:
- JWT authentication context needs fixing (using ALLOW_UNAUTHENTICATED=true)
- Swagger UI temporarily disabled due to composition error
- File upload endpoint needs multipart/form-data support

The API code is isolated in src/api/ directory to maintain separation
from the existing codebase, making it easy to maintain or contribute back.

test-api.sh

@@ -0,0 +1,133 @@
+#!/bin/bash
+
+# ConvertX API Test Script
+# This script tests the basic API functionality
+
+BASE_URL="http://localhost:3110/api/v1"
+EMAIL="test@example.com"
+PASSWORD="testpassword123"
+
+echo "🧪 ConvertX API Test Suite"
+echo "========================="
+echo ""
+
+# Function to pretty print JSON
+pretty_json() {
+    echo "$1" | jq '.' 2>/dev/null || echo "$1"
+}
+
+# 1. Test Health Endpoint
+echo "1️⃣ Testing Health Endpoint..."
+HEALTH=$(curl -s $BASE_URL/health)
+echo "Response:"
+pretty_json "$HEALTH"
+echo ""
+
+# 2. Test Swagger Documentation
+echo "2️⃣ Checking Swagger Documentation..."
+SWAGGER_STATUS=$(curl -s -o /dev/null -w "%{http_code}" $BASE_URL/swagger)
+if [ "$SWAGGER_STATUS" = "200" ]; then
+    echo "✅ Swagger documentation is available at $BASE_URL/swagger"
+else
+    echo "❌ Swagger documentation not accessible (HTTP $SWAGGER_STATUS)"
+fi
+echo ""
+
+# 3. Test Registration
+echo "3️⃣ Testing Registration..."
+REGISTER=$(curl -s -X POST $BASE_URL/auth/register \
+  -H "Content-Type: application/json" \
+  -d "{\"email\": \"$EMAIL\", \"password\": \"$PASSWORD\"}")
+echo "Response:"
+pretty_json "$REGISTER"
+
+# Extract token
+TOKEN=$(echo "$REGISTER" | jq -r '.data.token' 2>/dev/null)
+if [ "$TOKEN" = "null" ] || [ -z "$TOKEN" ]; then
+    echo "Registration might have failed. Trying login instead..."
+    
+    # Try login
+    LOGIN=$(curl -s -X POST $BASE_URL/auth/login \
+      -H "Content-Type: application/json" \
+      -d "{\"email\": \"$EMAIL\", \"password\": \"$PASSWORD\"}")
+    echo "Login Response:"
+    pretty_json "$LOGIN"
+    TOKEN=$(echo "$LOGIN" | jq -r '.data.token' 2>/dev/null)
+fi
+
+if [ "$TOKEN" = "null" ] || [ -z "$TOKEN" ]; then
+    echo "❌ Failed to get authentication token"
+    exit 1
+fi
+
+echo "✅ Got token: ${TOKEN:0:20}..."
+echo ""
+
+# 4. Test Current User
+echo "4️⃣ Testing Get Current User..."
+ME=$(curl -s $BASE_URL/auth/me \
+  -H "Authorization: Bearer $TOKEN")
+echo "Response:"
+pretty_json "$ME"
+echo ""
+
+# 5. Test List Converters
+echo "5️⃣ Testing List Converters..."
+CONVERTERS=$(curl -s $BASE_URL/converters \
+  -H "Authorization: Bearer $TOKEN")
+echo "Response (first 500 chars):"
+echo "$CONVERTERS" | jq '.' 2>/dev/null | head -c 500
+echo "..."
+echo ""
+
+# 6. Test Get Specific Converter
+echo "6️⃣ Testing Get Specific Converter (ffmpeg)..."
+FFMPEG=$(curl -s $BASE_URL/converters/ffmpeg \
+  -H "Authorization: Bearer $TOKEN")
+echo "Response (first 500 chars):"
+echo "$FFMPEG" | jq '.' 2>/dev/null | head -c 500
+echo "..."
+echo ""
+
+# 7. Test Format Support
+echo "7️⃣ Testing Format Support (PDF)..."
+PDF_CONVERTERS=$(curl -s $BASE_URL/converters/formats/pdf \
+  -H "Authorization: Bearer $TOKEN")
+echo "Response:"
+pretty_json "$PDF_CONVERTERS"
+echo ""
+
+# 8. Test List Jobs
+echo "8️⃣ Testing List Jobs..."
+JOBS=$(curl -s $BASE_URL/jobs \
+  -H "Authorization: Bearer $TOKEN")
+echo "Response:"
+pretty_json "$JOBS"
+echo ""
+
+# 9. Test Start Conversion (with dummy data)
+echo "9️⃣ Testing Start Conversion..."
+CONVERSION=$(curl -s -X POST $BASE_URL/conversions \
+  -H "Authorization: Bearer $TOKEN" \
+  -H "Content-Type: application/json" \
+  -d '{
+    "files": [{"name": "test.pdf"}],
+    "converter": "libreoffice",
+    "outputFormat": "docx"
+  }')
+echo "Response:"
+pretty_json "$CONVERSION"
+echo ""
+
+# Summary
+echo "📊 Test Summary"
+echo "==============="
+echo "✅ Health Check"
+echo "✅ Authentication"
+echo "✅ Converter Endpoints"
+echo "✅ Job Management"
+echo ""
+echo "🎉 All basic API tests completed!"
+echo ""
+echo "📝 Note: File conversion endpoints require actual file uploads."
+echo "   Use the Swagger UI at $BASE_URL/swagger for interactive testing."