[arzafran]

Summary

Cleaning several items in a cache category rescanned the whole category once per item, so a 30-folder DerivedData clean could take minutes. Each item now carries its removal method, set at scan time, and a clean scans each category once.

• The storage scan's git calls now go through the hardened automatic-git runner, so a repo's own git config (fsmonitor and similar) can't run a command during a scan.
• The login-shell PATH is resolved once per app run, and storage payloads share one date formatter.
• All safety rechecks before deletion are unchanged.

Fixes INC-485

Testing

• Two new tests in programaTests/StorageCategoriesTests.swift: scan count per clean, and git hardening. They compile but were not run locally; CI runs them.
• Not tried in a running app.

Demo Video

Not applicable, no visible UI change.

Checklist

• Tested via CI
• I added or updated tests for behavior changes
• I updated docs/changelog if needed (not needed)