Add Microsoft Teams cache as a junk category

[Vortrix5]

Summary

Teams keeps large Chromium-style caches. Classic Teams under %APPDATA%\Microsoft\Teams (Cache, Code Cache, GPUCache, Service Worker\CacheStorage); new Teams (MSIX) under %LOCALAPPDATA%\Packages\MSTeams_8wekyb3d8bbwe\LocalCache. Safe to clear, rebuilt on launch.

Where

Follow the existing app-cache categories in src/sifty/core/junk.py. Base dirs %APPDATA% and %LOCALAPPDATA%.

Acceptance criteria

• Category appears in sifty junk scan
• Only cache dirs, never anything holding auth/session (skip Local Storage, IndexedDB)
• Sandbox test in tests/test_junk.py
• pytest green

Tip

Use the /new-junk-category skill. There are two Teams flavors; covering classic alone is a fine first pass.