refactor(backend): clean up jail service, add error handling service

- Extract jail status/processing to helper functions
- Add error_handling.py service for centralized error handling
- Update config.py with validation and defaults
- Update .env.example with all config options
- Remove obsolete Tasks.md, add Service-Development.md
- Minor fixes across routers and services

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

backend/app/services/history_service.py

@@ -33,7 +33,7 @@ from app.models.history_domain import (
 )
 from app.repositories import fail2ban_db_repo
 from app.repositories import history_archive_repo as default_history_archive_repo
-from app.utils.constants import DEFAULT_PAGE_SIZE, MAX_PAGE_SIZE
+from app.utils.constants import DEFAULT_PAGE_SIZE
 from app.utils.fail2ban_db_utils import parse_data_json, ts_to_iso
 from app.utils.time_utils import since_unix
 
@@ -184,6 +184,7 @@ async def list_history(
     source: str = "fail2ban",
     page: int = 1,
     page_size: int = DEFAULT_PAGE_SIZE,
+    max_page_size: int = 500,
     http_session: aiohttp.ClientSession | None = None,
     geo_enricher: GeoEnricher | None = None,
     db: aiosqlite.Connection | None = None,
@@ -203,7 +204,8 @@ async def list_history(
         ip_filter: If given, restrict results to bans for this exact IP
             (or a prefix — the query uses ``LIKE ip_filter%``).
         page: 1-based page number (default: ``1``).
-        page_size: Maximum items per page, capped at ``MAX_PAGE_SIZE``.
+        page_size: Maximum items per page, capped at ``max_page_size``.
+        max_page_size: Deployment-configured maximum page size (default: ``500``).
         http_session: Optional shared :class:`aiohttp.ClientSession` (unused;
             kept for backward compatibility).
         geo_enricher: Optional async callable ``(ip: str) -> GeoInfo | None``.
@@ -216,7 +218,7 @@ async def list_history(
         :class:`~app.models.history_domain.DomainHistoryList` with paginated items
         and the total matching count.
     """
-    effective_page_size: int = min(page_size, MAX_PAGE_SIZE)
+    effective_page_size: int = min(page_size, max_page_size)
 
     # Build WHERE clauses dynamically.
     since: int | None = None