Fix setup persistence and load persisted runtime configuration

backend/app/routers/setup.py

@@ -10,10 +10,10 @@ from __future__ import annotations
 import structlog
 from fastapi import APIRouter, HTTPException, status
 
-from app.dependencies import AppDep, DbDep
+from app.dependencies import AppDep, DbDep, SettingsDep
 from app.models.setup import SetupRequest, SetupResponse, SetupStatusResponse, SetupTimezoneResponse
 from app.services import setup_service
-from app.utils.setup_state import set_setup_complete_cache
+from app.utils.setup_state import is_setup_complete_cached, set_setup_complete_cache
 
 log: structlog.stdlib.BoundLogger = structlog.get_logger()
 
@@ -25,14 +25,14 @@ router = APIRouter(prefix="/api/setup", tags=["setup"])
     response_model=SetupStatusResponse,
     summary="Check whether setup has been completed",
 )
-async def get_setup_status(db: DbDep) -> SetupStatusResponse:
+async def get_setup_status(app: AppDep) -> SetupStatusResponse:
     """Return whether the initial setup wizard has been completed.
 
     Returns:
         :class:`~app.models.setup.SetupStatusResponse` with ``completed``
         set to ``True`` if setup is done, ``False`` otherwise.
     """
-    done = await setup_service.is_setup_complete(db)
+    done = is_setup_complete_cached(app)
     return SetupStatusResponse(completed=done)
 
 
@@ -60,7 +60,7 @@ async def post_setup(
     Raises:
         HTTPException: 409 if setup has already been completed.
     """
-    if await setup_service.is_setup_complete(db):
+    if is_setup_complete_cached(app) or await setup_service.is_setup_complete(db):
         raise HTTPException(
             status_code=status.HTTP_409_CONFLICT,
             detail="Setup has already been completed.",
@@ -75,6 +75,14 @@ async def post_setup(
         session_duration_minutes=body.session_duration_minutes,
     )
     set_setup_complete_cache(app, True)
+    app.state.settings = app.state.settings.model_copy(
+        update={
+            "database_path": body.database_path,
+            "fail2ban_socket": body.fail2ban_socket,
+            "timezone": body.timezone,
+            "session_duration_minutes": body.session_duration_minutes,
+        }
+    )
     return SetupResponse()
 
 
@@ -83,7 +91,7 @@ async def post_setup(
     response_model=SetupTimezoneResponse,
     summary="Return the configured IANA timezone",
 )
-async def get_timezone(db: DbDep) -> SetupTimezoneResponse:
+async def get_timezone(settings: SettingsDep) -> SetupTimezoneResponse:
     """Return the IANA timezone configured during the initial setup wizard.
 
     The frontend uses this to convert UTC timestamps to the local time zone
@@ -94,5 +102,4 @@ async def get_timezone(db: DbDep) -> SetupTimezoneResponse:
         set to the stored IANA identifier (e.g. ``"UTC"`` or
         ``"Europe/Berlin"``), defaulting to ``"UTC"`` if unset.
     """
-    tz = await setup_service.get_timezone(db)
-    return SetupTimezoneResponse(timezone=tz)
+    return SetupTimezoneResponse(timezone=settings.timezone)