fix(providers): empty refresh must not resurface just-cleared synced models (#3181)

Empty refresh must not resurface just-cleared synced models (fixes the release-blocking provider-models-route test). Integrated into release/v3.8.10.

src/app/api/providers/[id]/models/route.ts

@@ -923,10 +923,52 @@ export async function GET(
         });
       }
 
-      const fallback = buildLocalCatalogResponse(
-        "No remote models discovered — using local catalog"
-      );
-      if (fallback) return fallback;
+      // Empty discovery just cleared THIS connection's synced cache (via
+      // persistDiscoveredModels([])). `providerSyncedModels` was read at the top
+      // of the handler and is now stale, so it must not leak the just-cleared
+      // models back into the response (#3148 made synced authoritative for the
+      // normal path; here we re-read the current state instead). Re-derive the
+      // local catalog from the provider's remaining synced models (union across
+      // its other connections) or the static catalog when none remain.
+      let freshSynced: Awaited<ReturnType<typeof getSyncedAvailableModels>> = [];
+      try {
+        freshSynced = await getSyncedAvailableModels(provider);
+      } catch {
+        /* DB unavailable — fall through to static catalog */
+      }
+      const freshRegistry = freshSynced.length
+        ? freshSynced.map((m) => ({
+            id: m.id,
+            name: m.name || m.id,
+            ...(m.apiFormat ? { apiFormat: m.apiFormat } : {}),
+            ...(m.supportedEndpoints ? { supportedEndpoints: m.supportedEndpoints } : {}),
+          }))
+        : getModelsByProviderId(provider) || [];
+      const freshSpecialty = freshSynced.length ? [] : getStaticModelsForProvider(provider) || [];
+      const freshLocal = mergeLocalCatalogModels(freshRegistry, freshSpecialty).map((model) => ({
+        id: model.id,
+        name: model.name || model.id,
+        ...((model as Record<string, unknown>).apiFormat
+          ? { apiFormat: (model as Record<string, unknown>).apiFormat as string | undefined }
+          : {}),
+        ...((model as Record<string, unknown>).supportedEndpoints
+          ? {
+              supportedEndpoints: (model as Record<string, unknown>).supportedEndpoints as
+                | string[]
+                | undefined,
+            }
+          : {}),
+        ...(freshRegistry.length > 0 ? { owned_by: provider } : {}),
+      }));
+      if (freshLocal.length > 0) {
+        return buildResponse({
+          provider,
+          connectionId,
+          models: freshLocal,
+          source: "local_catalog",
+          warning: "No remote models discovered — using local catalog",
+        });
+      }
 
       return buildResponse({
         provider,