Add cleanup audit manifests

[LeonidasZhak]

Summary

• add a structured cleanup manifest writer for each cleanup run
• record processed, skipped, and failed cleanup paths with action, type, size, and error details
• connect manual and automatic cleanup flows to save manifests under the app working directory
• document the user-visible audit record in the README

Safety model

This does not broaden the cleanup scope or change the existing age/category/whitelist rules. It only records the outcome after each selected path is processed. Protected extensions are still skipped, and failures remain non-fatal but are now visible in the manifest.

Tests

• python3 -m py_compile main.py utils/cleanupManifest.py utils/multiDeleteThread.py utils/selectVersion.py
• python3 -m unittest discover -s tests
• git diff --check

[LeonidasZhak]

Rebased this PR onto the current master and kept the newer macOS startup/crash-handling changes intact. The only manual conflict was the cleanup-manifest output directory; the existing top-level application constants remain the single source of truth. Validation: py_compile passed, all 5 unit tests passed, and git diff --check passed.