feat: authentication — register, login, JWT, tests

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/app/main.py

@@ -0,0 +1,19 @@
+from contextlib import asynccontextmanager
+
+from fastapi import FastAPI
+
+from app.api.auth import router as auth_router
+
+
+@asynccontextmanager
+async def lifespan(app: FastAPI):
+    yield
+
+
+app = FastAPI(title="Meeting Protocol Service", lifespan=lifespan)
+app.include_router(auth_router)
+
+
+@app.get("/api/health")
+async def health():
+    return {"status": "ok"}