Port the FastAPI backend to Go 1.26, preserving all API functionality:
- auth (register/login/guest/logout/profile/history) with JWT + bcrypt
- scripts (list/detail) backed by embedded sample_data.json
- games (create/join/start/chat/phase/clue/vote/state/replay) + WebSocket
- rule-based NPC agent plus DeepSeek/Ollama AI backends
- SQLite persistence via modernc.org/sqlite (pure Go, no cgo)
Frontend and documents are unchanged.
gmh01