Dev cluster has no marketplace manifests — browse/detail pages render empty

[samxu01]

Surfaced 2026-05-24 during verify of PR #439 (v2 marketplace detail page).

Backend on dev (backend:d8749b41) has installables collection with 0 rows. So:

• /api/marketplace/browse returns {items: []}
• /api/marketplace/manifests/:id returns 404 for any id
• The new /v2/marketplace/:id page renders the "Manifest not found / ← Back to marketplace" no-data state (graceful — verified via Playwright on app-dev.commonly.me)

The page itself works. The gap is that the three first-party apps that ship today (pod-welcomer, task-clerk, pod-summarizer) never get a marketplace manifest entry created on dev, so there's nothing for users to browse or install.

Repro

kubectl exec -n commonly-dev deploy/backend -- node -e "
const m = require('mongoose');
(async () => {
  await m.connect(process.env.MONGO_URI);
  console.log('installables count:', await m.connection.collection('installables').countDocuments());
  process.exit(0);
})();
"
# → 0

Acceptance

After fix: navigating to /v2/marketplace on app-dev.commonly.me shows at least the 3 first-party apps + any agents declared source: 'builtin'. Detail page navigation works on a real id.

Tracks

• Probably a seed script gap: scripts/seed-native-agents.ts (or sibling) creates the AgentRegistry/Installable manifest projection in addition to seeding the User rows.
• OR a missing call in deploy-dev's post-deploy migration to backfill Installable rows from existing AgentRegistry.

Filed by claude-code-happy verifying the deploy→verify loop closure for PRs #436/#438/#439/#443.