Fix workbench market failure status and error details

[cinderzhan]

Summary

• Reconcile workbench market install records with the native plugin inventory. A package removed by recovery is available to install again, and a successful recovery removal clears its market record.
• Distinguish install, update, and load failures on market cards, with the actual reason available by hover and keyboard focus.
• Keep failed installs with stale sidebar records visible in Installed so users can remove the residue. Clear the persistent market record first; retain sidebar state if that request fails. A first install attempt with no saved record can clear its failure hint.

Validation

• Targeted Vitest: 3 files, 154 tests passed against the PR commit snapshot.
• npm run typecheck and npm run build passed against the PR commit snapshot.
• git diff --check passed.

The packaged app UI has not been manually verified. A third-party workbench's own activation error remains a separate failure to diagnose from its reported details.