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

tests/test_api_expose.py

@@ -367,7 +367,7 @@ class TestPostRepublish:
         mock_settings.ha_discovery_enabled = True
         mock_settings.ha_discovery_prefix = "homeassistant"
 
-        with patch("app.api.routes.api.expose.get_settings", return_value=mock_settings):
+        with patch("app.api.routes.api.expose.build_runtime_settings", return_value=mock_settings):
             with patch("app.api.routes.api.expose.mqtt_manager") as mock_mqtt:
                 mock_mqtt.is_configured.return_value = True
                 mock_mqtt.is_connected = True
@@ -406,7 +406,7 @@ class TestPostRepublish:
         mock_settings.mqtt_enabled = True
         mock_settings.ha_discovery_enabled = True
 
-        with patch("app.api.routes.api.expose.get_settings", return_value=mock_settings):
+        with patch("app.api.routes.api.expose.build_runtime_settings", return_value=mock_settings):
             with patch("app.api.routes.api.expose.mqtt_manager") as mock_mqtt:
                 mock_mqtt.is_connected = False
                 resp = client.post(
@@ -475,3 +475,48 @@ class TestCatalogGrouping:
         components = {e["entity"]["component"] for e in catalog}
         assert "binary_sensor" in components
         assert "sensor" in components
+
+
+# ---------------------------------------------------------------------------
+# M5-fix2: DB-config → mqtt_status runtime assertion (Issue 2)
+# ---------------------------------------------------------------------------
+
+
+class TestMqttStatusReadsFromDB:
+    def test_get_expose_mqtt_configured_reflects_db_value(self, expose_client):
+        """GET /api/expose must return mqtt_configured=True when MQTT is enabled+configured
+        in the DB (app_config), even if the bootstrap env says disabled.
+
+        This verifies that _get_mqtt_status uses build_runtime_settings (DB-merged)
+        rather than bare get_settings() (bootstrap-only).
+        """
+        client, engine = expose_client
+        _login(client)
+
+        # Write MQTT_ENABLED=true and MQTT_BROKER_HOST into app_config directly.
+        # The lifespan seeds all config keys on startup, so we must UPDATE existing rows.
+        from datetime import UTC, datetime
+        from app.models.config import AppConfigEntry
+
+        now = datetime.now(UTC)
+        with Session(engine) as session:
+            for key, value in [("MQTT_ENABLED", "true"), ("MQTT_BROKER_HOST", "broker.test.local")]:
+                row = session.query(AppConfigEntry).filter(AppConfigEntry.key == key).first()
+                if row is None:
+                    session.add(AppConfigEntry(key=key, value=value, updated_at=now))
+                else:
+                    row.value = value
+                    row.updated_at = now
+            session.commit()
+
+        # The bootstrap env does NOT have MQTT enabled (default False in Settings).
+        # But GET /api/expose should still report mqtt_configured=True because it reads DB.
+        with patch("app.integrations.expose._REGISTRY", []):
+            resp = client.get("/api/expose")
+
+        assert resp.status_code == 200
+        mqtt_status = resp.json()["mqtt_status"]
+        assert mqtt_status["mqtt_configured"] is True, (
+            f"Expected mqtt_configured=True from DB settings, "
+            f"got {mqtt_status['mqtt_configured']!r}. Full status: {mqtt_status}"
+        )