feat: initial commit - Go + CGO captcha recognition service

Features:
- Go + CGO ONNX/OpenCV wrapper for high performance
- SQLite (default) / MySQL database support
- Optional Redis caching
- JWT authentication system
- Multiple captcha recognition APIs:
  - OCR text recognition
  - Slider captcha matching
  - Image similarity comparison
  - Rotation captcha detection
  - Object detection
- React frontend with install wizard
- Docker and docker-compose support
- Gitea CI/CD pipeline

Project structure:
- cmd/server: Main entry point
- internal/: Core business logic
- pkg/onnx: ONNX Runtime CGO wrapper
- pkg/opencv: OpenCV CGO wrapper
- web/: React frontend
- deploy/: Deployment configs
- scripts/: Utility scripts

deploy/config.example.yaml

@@ -0,0 +1,21 @@
+server:
+  host: 0.0.0.0
+  port: 6688
+  mode: release
+
+database:
+  type: sqlite
+  sqlite:
+    path: ./data/app.db
+
+redis:
+  enabled: false
+  host: localhost
+  port: 6379
+  db: 0
+
+jwt:
+  expire_time: 1440
+
+captcha:
+  model_path: ./models