refactor: Remove unused HTTPException imports from routers

After removing all try/except blocks that used HTTPException for domain
exception conversion, these imports are no longer needed in the routers.

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

backend/app/routers/bans.py

@@ -10,7 +10,7 @@ Manual ban and unban operations and the active-bans overview:
 
 from __future__ import annotations
 
-from fastapi import APIRouter, HTTPException, Request, status
+from fastapi import APIRouter, Request, status
 
 from app.dependencies import (
     AuthDep,
@@ -19,11 +19,9 @@ from app.dependencies import (
     GeoBatchLookupDep,
     HttpSessionDep,
 )
-from app.exceptions import JailNotFoundError, JailOperationError
 from app.models.ban import ActiveBanListResponse, BanRequest, UnbanAllResponse, UnbanRequest
 from app.models.jail import JailCommandResponse
 from app.services import ban_service, jail_service
-from app.exceptions import Fail2BanConnectionError
 
 router: APIRouter = APIRouter(prefix="/api/bans", tags=["Bans"])