fix: preserve manifest fallback for derived provider indexes

src/commands/models/list.provider-catalog.test.ts

@@ -210,6 +210,30 @@ describe("loadProviderCatalogModelsForList", () => {
     expect(providerDiscoveryMocks.resolveOwningPluginIdsForProvider).not.toHaveBeenCalled();
   });
 
+  it("falls back to manifest ownership when the plugin index is derived", async () => {
+    providerDiscoveryMocks.loadPluginRegistrySnapshotWithMetadata.mockReturnValueOnce({
+      source: "derived",
+      snapshot: {
+        plugins: [],
+      },
+      diagnostics: [],
+    });
+
+    await expect(
+      resolveProviderCatalogPluginIdsForFilter({
+        cfg: baseParams.cfg,
+        env: baseParams.env,
+        providerFilter: "moonshot",
+      }),
+    ).resolves.toEqual(["moonshot"]);
+
+    expect(providerDiscoveryMocks.resolveOwningPluginIdsForProvider).toHaveBeenCalledWith({
+      provider: "moonshot",
+      config: baseParams.cfg,
+      env: baseParams.env,
+    });
+  });
+
   it("does not fall back to legacy manifest ownership for disabled persisted plugin owners", async () => {
     providerDiscoveryMocks.resolveProviderOwners
       .mockReturnValueOnce([])

src/commands/models/list.provider-catalog.ts

@@ -76,7 +76,7 @@ function resolveInstalledIndexPluginIdsForProviderFilter(params: {
     cache: true,
   });
   if (snapshot.source !== "persisted" && snapshot.source !== "provided") {
-    return [];
+    return undefined;
   }
   const index = snapshot.snapshot;
   const pluginIds = [