M5: use DB-merged runtime settings for MQTT/discovery; add MQTT test button; move Expose panel into config accordion

app/api/routes/api/config.py

@@ -75,8 +75,11 @@ def put_config(
             detail="invalid config submission",
         ) from exc
 
-    # Re-read settings after save (save_config_updates clears the settings cache)
-    refreshed_settings = get_settings()
+    # Re-read settings after save (save_config_updates clears the settings cache).
+    # Use build_runtime_settings so the reconnect picks up DB-stored values, not
+    # just the bootstrap env (otherwise a broker configured via the UI is ignored).
+    from app.services.config_page import build_runtime_settings
+    refreshed_settings = build_runtime_settings(db, get_settings())
 
     # Reconnect MQTT client if any MQTT setting was updated.
     if mqtt_keys_submitted:

app/api/routes/api/expose.py

@@ -23,6 +23,7 @@ from sqlalchemy.orm import Session
 from app.api.routes.api.deps import require_csrf, require_session
 from app.config import get_settings
 from app.dependencies import get_db
+from app.services.config_page import build_runtime_settings
 from app.integrations.expose import CatalogEntry, build_catalog
 from app.integrations.mqtt import mqtt_manager
 from app.models.expose import ExposedEntityToggle
@@ -48,9 +49,9 @@ router = APIRouter(prefix="/api", tags=["api-expose"])
 # ---------------------------------------------------------------------------
 
 
-def _get_mqtt_status() -> MqttStatusSchema:
-    """Build MQTT/Discovery status from live runtime state."""
-    settings = get_settings()
+def _get_mqtt_status(db: Session) -> MqttStatusSchema:
+    """Build MQTT/Discovery status from live runtime state (DB-merged settings)."""
+    settings = build_runtime_settings(db, get_settings())
     return MqttStatusSchema(
         mqtt_configured=mqtt_manager.is_configured(settings),
         mqtt_connected=mqtt_manager.is_connected,
@@ -87,7 +88,7 @@ def _build_response_data(
     """Return (catalog_entries, mqtt_status) for building GET / PUT responses."""
     catalog = build_catalog(session)
     catalog_schema = [_entry_to_schema(e) for e in catalog]
-    mqtt_status = _get_mqtt_status()
+    mqtt_status = _get_mqtt_status(session)
     return catalog_schema, mqtt_status
 
 
@@ -179,7 +180,7 @@ def post_expose_republish(
     Returns a status indicating whether the publish was attempted (or skipped
     because MQTT / discovery is not enabled / connected).
     """
-    settings = get_settings()
+    settings = build_runtime_settings(db, get_settings())
     if not (settings.mqtt_enabled and settings.ha_discovery_enabled and mqtt_manager.is_connected):
         return RepublishResponse(
             ok=False,