feat: add connections dashboard with background health checks

- Add /connections page showing all integrations with online/offline status
- Add background health checker that polls Evotor API every 10 minutes
- Add is_online and last_checked_at fields to evotor_connections table
- Replace Evotor navbar link with unified Connections link
- Redirect connect/disconnect flows to /connections
- Add Alembic migration for new columns

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

web/main.py

@@ -1,11 +1,31 @@
-from fastapi import FastAPI
+import asyncio
+from contextlib import asynccontextmanager
+
+from fastapi import FastAPI, Depends, Request
+from fastapi.responses import RedirectResponse
 from fastapi.staticfiles import StaticFiles
 from starlette.middleware.sessions import SessionMiddleware
 
+from web.auth import get_current_user
 from web.config import settings
+from web.health_checker import health_check_loop
+from web.models import User
 from web.routes import auth, profile, reset, evotor
+from web.routes import connections
 
-app = FastAPI(title="EvoSync — Личный кабинет")
+
+@asynccontextmanager
+async def lifespan(app: FastAPI):
+    task = asyncio.create_task(health_check_loop(settings.HEALTH_CHECK_INTERVAL_SECONDS))
+    yield
+    task.cancel()
+    try:
+        await task
+    except asyncio.CancelledError:
+        pass
+
+
+app = FastAPI(title="EvoSync — Личный кабинет", lifespan=lifespan)
 
 app.add_middleware(SessionMiddleware, secret_key=settings.SECRET_KEY)
 app.mount("/static", StaticFiles(directory="web/static"), name="static")
@@ -14,3 +34,11 @@ app.include_router(auth.router)
 app.include_router(profile.router)
 app.include_router(reset.router)
 app.include_router(evotor.router)
+app.include_router(connections.router)
+
+
+@app.get("/")
+def home(request: Request, user: User | None = Depends(get_current_user)):
+    if user:
+        return RedirectResponse("/profile", 302)
+    return RedirectResponse("/login", 302)