Move the Updates plugin's pure decision logic (recommended/additional
commands, panel visibility, installation labels, version formatting)
into a sibling updatesLogic.ts module so it can be unit tested directly,
matching the workspace-tasks multi-file plugin layout. The plugin file
is now thin rendering glue that imports those helpers.
Add unit tests for the extracted logic and render smoke tests that
exercise the panel through its public contribution API, including that
Run actions wire to the terminal with the "pi.plugin": "updates"
metadata. No behavior change; the beta label stays.
