fix 500

backend/app/lifespan.py

@@ -54,6 +54,22 @@ async def lifespan(app: FastAPI):
     set_pg_pool(pg_pool)
     app.state.pg_pool = pg_pool
 
+    # Fail fast if Flyway routines are missing (otherwise heartbeat silently goes stale in FE).
+    async with pg_pool.acquire() as conn:
+        fn_ok = await conn.fetchval(
+            """
+            select exists(
+              select 1
+              from pg_proc p
+              join pg_namespace n on n.oid = p.pronamespace
+              where n.nspname = 'ems'
+                and p.proname = 'fn_update_heartbeat'
+            )
+            """
+        )
+        if not fn_ok:
+            raise RuntimeError("Missing DB routine: ems.fn_update_heartbeat")
+
     app.state.ws_log_handler = WSLogHandler()
     app.state.ws_log_handler.setLevel(logging.INFO)
     logging.getLogger().addHandler(app.state.ws_log_handler)

backend/app/routers/full_status.py

@@ -126,9 +126,9 @@ async def get_site_status_full(
     tomorrow_slots = int(bundle.get("tomorrow_price_slot_count") or 0)
 
     now_utc = datetime.now(timezone.utc)
-    hb_last = hb_row.get("last_seen") if hb_row else None
+    hb_last = _parse_ts(hb_row.get("last_seen") if hb_row else None)
     hb_age = _age_seconds(hb_last)
-    inv_measured = inv_row.get("measured_at") if inv_row else None
+    inv_measured = _parse_ts(inv_row.get("measured_at") if inv_row else None)
     inv_age = _age_seconds(inv_measured)
 
     next_start, next_bat = _next_plan_interval(intervals, now_utc)