Detect, and possibly fix, odd/bad MAS app states

Problem(s) addressed

MAS apps can get into odd/bad states.

Detect, and possibly fix, them.

e.g., more than one app with the same app ID can be installed under /Applications.

Proposed solution(s)

Non-mutually exclusive solutions:

• mas doctor: detect (and possibly fix) any problems we can
  • Possibly interactive, automatic, filterable, etc.
• Include warnings when running other commands normally
• Change default command outputs to make odd/bad states more noticeable, e.g.:
  • Include app paths in default mas list output, either for all apps or just for those with duplicate app IDs
• Allow explicitly asking for specific states from various commands, e.g.:
  • mas list —duplicate-app-ids

Alternative solution(s)

No response

Additional context

No response

Start by reviewing the existing mas list command and the proposed mas doctor entry point, using duplicate app IDs under /Applications as the concrete case. The issue does not identify files, tests, a complete set of bad states, or whether fixes should be automatic, so the scope and definition of done need maintainer decisions before implementation.