Let users choose the metadata generation model (#3215)

Expose Automatic and Manual metadata model selection in Host Settings, preserve existing configured fallbacks, and keep structured generation resilient through discovered candidates. Includes Playwright coverage, translations, public documentation, and settings-row alignment polish.

packages/app/src/utils/host-routes.test.ts

@@ -248,6 +248,7 @@ describe("host settings section slugs", () => {
     expect(normalizeHostSectionSlug("connections")).toBe("connections");
     expect(normalizeHostSectionSlug("pair-device")).toBe("pair-device");
     expect(normalizeHostSectionSlug("agents")).toBe("agents");
+    expect(normalizeHostSectionSlug("metadata")).toBe("metadata");
     expect(normalizeHostSectionSlug("workspaces")).toBe("workspaces");
     expect(normalizeHostSectionSlug("projects")).toBe("projects");
     expect(normalizeHostSectionSlug("providers")).toBe("providers");

packages/app/src/utils/host-routes.ts

@@ -512,6 +512,7 @@ export const HOST_SECTION_SLUGS = [
   "connections",
   "pair-device",
   "agents",
+  "metadata",
   "workspaces",
   "providers",
   "usage",