Refactor routers to use explicit FastAPI app dependencies

backend/app/dependencies.py

@@ -15,7 +15,7 @@ import aiohttp
 import aiosqlite
 import structlog
 from apscheduler.schedulers.asyncio import AsyncIOScheduler  # type: ignore[import-untyped]
-from fastapi import Depends, HTTPException, Request, status
+from fastapi import Depends, FastAPI, HTTPException, Request, status
 
 from app.config import Settings
 from app.models.auth import Session
@@ -181,6 +181,11 @@ async def get_app_state(request: Request) -> AppState:
     return cast("AppState", request.app.state)
 
 
+async def get_app(request: Request) -> FastAPI:
+    """Provide the FastAPI application instance for the current request."""
+    return request.app
+
+
 async def get_server_status(request: Request) -> ServerStatus:
     """Return the cached fail2ban server status snapshot from app state."""
     state = cast("AppState", request.app.state)
@@ -264,4 +269,5 @@ Fail2BanStartCommandDep = Annotated[str, Depends(get_fail2ban_start_command)]
 ServerStatusDep = Annotated[ServerStatus, Depends(get_server_status)]
 PendingRecoveryDep = Annotated[PendingRecovery | None, Depends(get_pending_recovery)]
 AppStateDep = Annotated[AppState, Depends(get_app_state)]
+AppDep = Annotated[FastAPI, Depends(get_app)]
 AuthDep = Annotated[Session, Depends(require_auth)]