Implement youaskm3 CLI app validation and registration (Phase 2)

[enricopiovesan]

Summary

Wire up the youaskm3 setup path using traverse-cli app validate and traverse-cli app register so the app can be validated and registered into a local Traverse workspace, enabling the runtime to load the registered app without private internals.

Why

Specs 044 and 046 are both approved. youaskm3 is the primary reference app for the full Phase 2 path. This ticket proves that a downstream app can use the public CLI registration surface to set up Traverse, completing the local developer setup story.

Definition of Done

• traverse-cli app validate --manifest manifests/youaskm3/app.manifest.json --json exits 0
• traverse-cli app register --manifest manifests/youaskm3/app.manifest.json --workspace local-default --json exits 0 and writes durable workspace state
• Runtime loads registered workspace state without private internals
• youaskm3 UI can invoke the registered workflow through the HTTP API
• Setup steps documented in apps/youaskm3/web-react/README.md
• No fake registration path introduced

Governing specs

• 044-application-bundle-manifest (approved)
• 046-public-cli-app-registration (approved)

Depends on

#12 (youaskm3 app manifest), #13 (HTTP client)