feat: Meeting Assistant MVP - Complete implementation

Enterprise Meeting Knowledge Management System with:

Backend (FastAPI):
- Authentication proxy with JWT (pj-auth-api integration)
- MySQL database with 4 tables (users, meetings, conclusions, actions)
- Meeting CRUD with system code generation (C-YYYYMMDD-XX, A-YYYYMMDD-XX)
- Dify LLM integration for AI summarization
- Excel export with openpyxl
- 20 unit tests (all passing)

Client (Electron):
- Login page with company auth
- Meeting list with create/delete
- Meeting detail with real-time transcription
- Editable transcript textarea (single block, easy editing)
- AI summarization with conclusions/action items
- 5-second segment recording (efficient for long meetings)

Sidecar (Python):
- faster-whisper medium model with int8 quantization
- ONNX Runtime VAD (lightweight, ~20MB vs PyTorch ~2GB)
- Chinese punctuation processing
- OpenCC for Traditional Chinese conversion
- Anti-hallucination parameters
- Auto-cleanup of temp audio files

OpenSpec:
- add-meeting-assistant-mvp (47 tasks, archived)
- add-realtime-transcription (29 tasks, archived)

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

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

backend/app/main.py

@@ -0,0 +1,44 @@
+from fastapi import FastAPI
+from fastapi.middleware.cors import CORSMiddleware
+from contextlib import asynccontextmanager
+
+from .database import init_db_pool, init_tables
+from .routers import auth, meetings, ai, export
+
+
+@asynccontextmanager
+async def lifespan(app: FastAPI):
+    # Startup
+    init_db_pool()
+    init_tables()
+    yield
+    # Shutdown (cleanup if needed)
+
+
+app = FastAPI(
+    title="Meeting Assistant API",
+    description="Enterprise meeting knowledge management API",
+    version="1.0.0",
+    lifespan=lifespan,
+)
+
+# CORS configuration for Electron client
+app.add_middleware(
+    CORSMiddleware,
+    allow_origins=["*"],
+    allow_credentials=True,
+    allow_methods=["*"],
+    allow_headers=["*"],
+)
+
+# Include routers
+app.include_router(auth.router, prefix="/api", tags=["Authentication"])
+app.include_router(meetings.router, prefix="/api", tags=["Meetings"])
+app.include_router(ai.router, prefix="/api", tags=["AI"])
+app.include_router(export.router, prefix="/api", tags=["Export"])
+
+
+@app.get("/api/health")
+async def health_check():
+    """Health check endpoint."""
+    return {"status": "healthy", "service": "meeting-assistant"}