[codex] make Home failures actionable

[r3dbars]

Summary

• Converts Home failure alerts from OK-only messages into actionable alerts with a primary Try again action.
• Normalizes delete/rename failure copy so raw Error.localizedDescription does not appear in the user-facing message.
• Keeps technical error text behind an explicit Copy Details affordance when an underlying error exists.
• Adds fast coverage for the Home failure copy contract.

Surfaces Fixed

• Home root failure alert path for copy/open/reveal/re-transcribe/delete/rename/failed-meeting cleanup failures.

Surfaces Held

• Agent connection setup errors, paste-last feedback, dictation overlay messages, and meeting overlay alerts are still separate WS4.3 candidates.

Checks

• bash run-tests.sh --filter HomeRootAlertPolicy — 11 passed.
• bash run-tests.sh — 11221 passed.
• bash build-deps.sh --force — passed.
• bash build.sh --no-open — app compiled and signed, then failed at launch smoke with _LSOpenURLsWithCompletionHandler() failed with error -10810; treated as local launch-smoke YELLOW, not a code compile failure.

Maestro Lanes

lanes used: Codex=implemented, built, tested, committed, pushed, opened draft PR; Claude=skipped, scope was small and local; Local=surface ranking via /Users/redbars/.codex/maestro/runs/20260703T001713Z-ws43-error-surface-ranking-local; Windows=skipped, no long-running draft implementation needed.