Improve scan recovery and overview accessibility

[RasputinKaiser]

Summary

• replace stale recent-scan alert/panel chaining with an explicit recovery decision
• let users choose the folder again, forget the stale scan, or cancel safely
• expose Storage Map rows as accessible buttons with selection state and a named tree action
• start the selection-driven inspector closed so cold-launch content gets the full window
• add recovery-state regression coverage

Why

Recent scans whose security-scoped bookmarks could no longer resolve immediately opened a folder panel while reporting an error, making the recovery sequence abrupt and unclear. Storage Map rows also surfaced as unknown accessibility elements, and the empty inspector consumed substantial cold-launch space on wide displays.

User impact

Stale access now produces a clear three-way decision before any folder picker appears. VoiceOver and other accessibility clients receive actionable Storage Map buttons. The initial overview has more room while the inspector remains available from the toolbar.

Validation

• swift test --scratch-path /tmp/storagescope-luna-fixes-swift-test — 204 tests in 20 suites passed
• ./script/build_and_run.sh --verify — app bundle built, signed, and launched
• exact-build visual inspection confirmed the inspector starts closed
• exact-build accessibility inspection confirmed Storage Map rows expose button roles
• git diff --check