T-10: Fix get_geo_batch_lookup for proper injection with GeoCache instance

Instead of returning a bound method (geo_cache.lookup_batch), now inject
the GeoCache instance directly into routers and services. This provides
proper runtime isolation since T-04 made GeoCache a proper object.

Changes:
- Remove get_geo_batch_lookup() dependency provider
- Add GeoCacheDep type alias for injecting GeoCache instances
- Update all routers (bans, blocklist, dashboard, jails) to use GeoCacheDep
- Update ban_service, blocklist_service, jail_service to accept GeoCache
- Update service protocols to match new signatures
- Update docstrings to reference GeoCache methods instead of module functions

All callers now call geo_cache.lookup_batch(...) directly instead of
geo_batch_lookup(...), providing real dependency injection with proper
testing isolation.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

backend/app/dependencies.py

@@ -20,7 +20,6 @@ from fastapi import Depends, FastAPI, HTTPException, Request, status
 from app.config import Settings
 from app.models.auth import Session
 from app.models.config import PendingRecovery
-from app.models.geo import GeoBatchLookup
 from app.models.server import ServerStatus
 from app.repositories.protocols import (
     BlocklistRepository,
@@ -72,7 +71,7 @@ def _session_cache_enabled(settings: Settings) -> bool:
 
 
 def _build_app_context(request: Request) -> ApplicationContext:
-    state = cast(ApplicationState, request.app.state)
+    state = cast("ApplicationState", request.app.state)
     session_cache = getattr(state, "session_cache", None)
     if session_cache is None:
         session_cache = NoOpSessionCache()
@@ -194,15 +193,10 @@ async def get_fail2ban_start_command(settings: Settings = Depends(get_settings))
     return settings.fail2ban_start_command
 
 
-async def get_geo_batch_lookup(request: Request) -> GeoBatchLookup:
-    """Provide the geo batch lookup method from the application's GeoCache instance."""
-    geo_cache: GeoCache = request.app.state.geo_cache
-    return geo_cache.lookup_batch  # type: ignore[return-value]
-
-
 async def get_geo_cache(request: Request) -> GeoCache:
     """Provide the application's GeoCache instance."""
-    return request.app.state.geo_cache
+    geo_cache: GeoCache = cast("GeoCache", request.app.state.geo_cache)
+    return geo_cache
 
 
 async def get_session_cache(app_context: Annotated[ApplicationContext, Depends(get_app_context)]) -> SessionCache:
@@ -365,7 +359,7 @@ SchedulerDep = Annotated[AsyncIOScheduler, Depends(get_scheduler)]
 Fail2BanSocketDep = Annotated[str, Depends(get_fail2ban_socket)]
 Fail2BanConfigDirDep = Annotated[str, Depends(get_fail2ban_config_dir)]
 Fail2BanStartCommandDep = Annotated[str, Depends(get_fail2ban_start_command)]
-GeoBatchLookupDep = Annotated[GeoBatchLookup, Depends(get_geo_batch_lookup)]
+GeoCacheDep = Annotated[GeoCache, Depends(get_geo_cache)]
 ServerStatusDep = Annotated[ServerStatus, Depends(get_server_status)]
 PendingRecoveryDep = Annotated[PendingRecovery | None, Depends(get_pending_recovery)]
 SessionCacheDep = Annotated[SessionCache, Depends(get_session_cache)]