feat: Add AI report generation with DIFY integration

- Add Users table for display name resolution from AD authentication
- Integrate DIFY AI service for report content generation
- Create docx assembly service with image embedding from MinIO
- Add REST API endpoints for report generation and download
- Add WebSocket notifications for generation progress
- Add frontend UI with progress modal and download functionality
- Add integration tests for report generation flow

Report sections (Traditional Chinese):
- 事件摘要 (Summary)
- 時間軸 (Timeline)
- 參與人員 (Participants)
- 處理過程 (Resolution Process)
- 目前狀態 (Current Status)
- 最終處置結果 (Final Resolution)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

app/core/config.py

@@ -32,6 +32,15 @@ class Settings(BaseSettings):
     MINIO_BUCKET: str = "task-reporter-files"
     MINIO_SECURE: bool = False  # Use HTTPS
 
+    # DIFY AI Service
+    DIFY_BASE_URL: str = "https://dify.theaken.com/v1"
+    DIFY_API_KEY: str = ""  # Required for report generation
+    DIFY_TIMEOUT_SECONDS: int = 120  # AI generation can take time
+
+    # Report Generation
+    REPORT_MAX_MESSAGES: int = 200  # Summarize if exceeded
+    REPORT_STORAGE_PATH: str = "reports"  # MinIO path prefix for reports
+
     class Config:
         env_file = ".env"
         case_sensitive = True