Track Ghostel lifecycle and progress metadata

[tninja]

Summary

• Wire Ghostel OSC 133 command-start / command-finish hooks into AI Code session metadata.
• Wrap Ghostel OSC 9;4 progress handling so AI Code records progress state while preserving Ghostel's original progress handler.
• Add focused ERT coverage for lifecycle hook installation, metadata updates, non-AI buffer filtering, and progress delegation.

Notes

This intentionally treats command lifecycle and progress as structured metadata signals only. It does not use them yet to trigger tests/reviews or declare an AI response complete.

Tests

Not run locally: this environment does not have Emacs installed.