fix: sync directive plan renders to peers

[atomantic]

Summary

• Include completed Creative Director directive-plan image and video renders in project asset manifests.
• Preserve manifest safety, missing-file skips, and linked-collection behavior for legacy scene renders.
• Add coverage for valid, duplicate, unfinished, and non-render plan results.

Tests

• NODE_ENV=test npm test -- --run services/sharing/peerSyncAssets.test.js
• NODE_ENV=test npm test -- --run services/sharing

Closes #4159