Bundle the locked Mobile Next runtime and preserve built-in MCP settings.
Improve USB discovery, selection, preview and disconnect behavior.
Fix macOS layout, tighten chat spacing and show AI operation status.
Keep observation screenshots internal unless requested and allow tasks to run until completion or cancellation.
Update runtime packaging, ignore generated mobile assets and add regression coverage.
Validation: 34 frontend tests, vue-tsc, and go test -race ./internal/...
