Fix MEDIUM findings from 2026-09-24 maintenance review

- Backend retries DB connection at startup (up to 180s) so host reboots
  no longer crash-loop it; add backend and frontend healthchecks
- Docker log rotation (json-file 10m x 3) on all services
- ntfy alerts use X-Real-IP (set by nginx after real_ip resolution)
  instead of the client-controlled first X-Forwarded-For entry
- Frontend build on Node 24 LTS with package-lock.json + npm ci;
  axios 1.20.0, vite 5.4.21
- README: backup/restore/rollback runbook, real-IP proxy trust notes
- Release-Notes/v1.1.md; version 1.1.0

Co-Authored-By: Claude Opus 5.5 <[email protected]>

backend/app/main.py

@@ -1,5 +1,7 @@
+import asyncio
 import logging
 import random
+import time
 from contextlib import asynccontextmanager
 
 from fastapi import FastAPI, WebSocket, WebSocketDisconnect
@@ -67,8 +69,25 @@ async def _add_index_if_missing(conn, index_name: str, table: str, column: str):
             raise
 
 
+async def _wait_for_db(timeout: float = 180, interval: float = 2) -> None:
+    """Retry until MySQL accepts connections. On host reboot Docker's restart
+    policy ignores depends_on, so the backend can start before the DB is up."""
+    deadline = time.monotonic() + timeout
+    while True:
+        try:
+            async with engine.connect() as conn:
+                await conn.execute(text("SELECT 1"))
+            return
+        except OperationalError as e:
+            if time.monotonic() >= deadline:
+                raise
+            logger.info("Database not ready (%s), retrying in %ss", e.orig, interval)
+            await asyncio.sleep(interval)
+
+
 @asynccontextmanager
 async def lifespan(app: FastAPI):
+    await _wait_for_db()
     # Create tables on startup (Alembic handles migrations in prod, this is a safety net)
     async with engine.begin() as conn:
         await conn.run_sync(Base.metadata.create_all)