Fix filter_config router import and mark Task 3 complete

Docs/Tasks.md

@@ -62,6 +62,8 @@ The `GET /api/config` log preview endpoint (`POST /api/config/preview-log`) call
 
 ### Task 3 — Fix filter_config router: import ConfigWriteError from the correct module
 
+**Status:** Completed
+
 **Severity:** Bug
 
 **Where:**

backend/app/routers/filter_config.py

@@ -5,7 +5,7 @@ from typing import Annotated
 from fastapi import APIRouter, HTTPException, Path, Query, status
 
 from app.dependencies import AuthDep, Fail2BanConfigDirDep, Fail2BanSocketDep
-from app.services.config_file_service import ConfigWriteError
+from app.exceptions import ConfigWriteError
 from app.models.config import (
     AssignFilterRequest,
     FilterConfig,

backend/app/services/filter_config_service.py

@@ -18,7 +18,7 @@ from pathlib import Path
 
 import structlog
 
-from app.exceptions import FilterInvalidRegexError
+from app.exceptions import ConfigWriteError, FilterInvalidRegexError, JailNotFoundInConfigError
 from app.helpers.config_file_helpers import (
     _get_active_jail_names,
     _parse_jails_sync,
@@ -32,7 +32,7 @@ from app.models.config import (
     FilterListResponse,
     FilterUpdateRequest,
 )
-from app.services.config_file_service import _TRUE_VALUES, ConfigWriteError, JailNotFoundInConfigError
+from app.services.config_file_service import _TRUE_VALUES
 from app.utils import conffile_parser
 
 log: structlog.stdlib.BoundLogger = structlog.get_logger()