fix(tui): ignore stale auto review completions

[shiny-code-bot]

Summary

• carry Auto Review owner session and worktree-base metadata through agent status updates
• ignore stale or cross-session Auto Review completions before they can clear active review state or surface findings
• guard direct background-review lifecycle completions with the same session/snapshot identity checks
• add regressions for stale terminal completions, cross-session completions, skip-sentinel completions, and direct finished events

Validation

• cargo test -p code-tui stale_auto_review --features test-helpers
• cargo test -p code-tui stale_background_review_finished_event_does_not_clear_current_review --features test-helpers
• cargo test -p code-tui cross_session_auto_review_status_does_not_surface_findings --features test-helpers
• cargo test -p code-tui background_review_observe --features test-helpers
• ./build-fast.sh

Notes

This is a first reliability slice for #76. Review agents flagged the skip-sentinel ordering hole and the direct-finished-event bypass; both are covered here before merge.