Fix HIGH priority issues: unbounded queries, rate limiting, health checks

Issue #3 - Unbounded Query Results (OOM):
- get_all_archived_history() now uses keyset pagination with bounded max_rows (50k default)
- Added 'id' field to records from get_archived_history() and get_archived_history_keyset()
- Protocol signature updated with page_size, max_rows, last_ban_id params

Issue #7 - Docker Health Check Fails:
- Added curl to Dockerfile.backend runtime image
- HEALTHCHECK now uses 'curl -f http://localhost:8000/api/health'
- compose.prod.yml: increased start_period to 40s, timeout to 10s
- Frontend healthcheck proxies to backend /api/health

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

backend/app/services/health_service.py

@@ -16,7 +16,7 @@ from typing import TypeVar, cast
 import structlog
 
 from app import __version__
-from app.models.config import ServiceStatusResponse
+from app.models.config_domain import DomainServiceStatus
 from app.models.server import ServerStatus
 from app.utils.constants import FAIL2BAN_SOCKET_TIMEOUT_FAST
 from app.utils.fail2ban_client import (
@@ -69,7 +69,7 @@ async def _safe_get_typed(
 async def get_service_status(
     socket_path: str,
     probe_fn: Callable[[str], Awaitable[ServerStatus]] | None = None,
-) -> ServiceStatusResponse:
+) -> DomainServiceStatus:
     """Return fail2ban service health status with log configuration.
 
     Delegates to an injectable *probe_fn* (defaults to
@@ -80,7 +80,7 @@ async def get_service_status(
         probe_fn: Optional probe function.
 
     Returns:
-        :class:`~app.models.config.ServiceStatusResponse`.
+        :class:`~app.models.config_domain.DomainServiceStatus`.
     """
     if probe_fn is None:
         raise ValueError(
@@ -110,7 +110,7 @@ async def get_service_status(
         jail_count=server_status.active_jails,
     )
 
-    return ServiceStatusResponse(
+    return DomainServiceStatus(
         online=server_status.online,
         version=__version__,
         jail_count=server_status.active_jails,