feat: MVP-2 Alpha - Tauri desktop, auth, AI gateway, sync engine and server infrastructure

Client:
- Add Tauri desktop app integration (src-tauri config, icons, main.rs)
- Add authentication system (Supabase client, login/register pages, AuthContext)
- Add AI plugin system (plugin loader, remote/local fallback, useAI hook)
- Add sync engine (SyncEngine, OfflineQueue, NetworkManager, SyncContext)
- Add storage layer abstraction (interfaces, factory pattern, writeWithLog)
- Add PWA install prompt, network status hook, mode manager
- Add HTTP API client and utility modules (platform, uuid)
- Refactor feynman, flashcards, notes, pomodoro, sm2, storage modules

Server:
- Add AI gateway service (Python/FastAPI: chains, providers, routers, middleware)
- Add sync service (Go: handlers, middleware, protobuf definitions)
- Add Docker infrastructure (docker-compose, Dockerfiles)
- Add shared protobuf definitions (ai_service, sync_service, common)

Docs:
- Update architecture design, tech selection ADR, sync strategy docs

Config:
- Add .env.example template, update .gitignore, vite and tsconfig

Author: Aparencia

.env.example

@@ -0,0 +1,39 @@
+# ===========================================
+# 课伴 (KeBan) MVP-2 Alpha 环境变量模板
+# ===========================================
+# 复制此文件为 .env 并填入实际值
+
+# --- 前端 (client/) ---
+
+# Supabase 认证（在 https://supabase.com 创建项目后获取）
+VITE_SUPABASE_URL=https://your-project-id.supabase.co
+VITE_SUPABASE_ANON_KEY=your-anon-key
+
+# 后端服务地址
+VITE_API_BASE_URL=http://localhost:8080
+VITE_AI_GATEWAY_URL=http://localhost:8000
+VITE_API_HEALTH_URL=/api/health
+VITE_SYNC_SERVER_URL=http://localhost:8080
+
+# --- 后端 (server/) ---
+
+# AI 模型 API Key（在对应平台注册获取）
+# 通义千问：https://dashscope.aliyun.com
+QWEN_API_KEY=sk-your-qwen-api-key
+
+# DeepSeek：https://platform.deepseek.com
+DEEPSEEK_API_KEY=sk-your-deepseek-key
+
+# 智谱 GLM（可选，作为备选模型）：https://open.bigmodel.cn
+GLM_API_KEY=
+
+# 数据库（Docker Compose 默认值，本地开发无需修改）
+DATABASE_URL=postgresql://keban:keban_dev@localhost:5432/keban
+REDIS_URL=redis://localhost:6379
+
+# JWT 安全密钥（生产环境必须修改为随机字符串）
+JWT_SECRET=change-this-to-a-random-string-in-production
+
+# 服务端口
+SYNC_SERVICE_PORT=8080
+AI_GATEWAY_PORT=8000

.gitignore

@@ -9,12 +9,19 @@ dist/
 build/
 *.exe
 *.wasm
+*.pdb
+*.dll
+client/src-tauri/target/
 
 # IDE
 .vscode/
 .idea/
 *.swp
 *.swo
+.qoder/
+
+# Git worktree
+vPpiCi/
 
 # OS
 .DS_Store