sync and publish name the Rebase-Review Gate by its display name

The help and exit-42 cause texts still said "rebase-review gate" after the display
name was settled; the generated reference and CONTRACT row follow.

Files changed:
- CHANGES.md
- VERSION
- docs/reference/commands/git.md
- docs/reference/exit-codes.md
- tools/CONTRACT.md
- tools/chemenu/commands/git_publish.py

Co-Authored-By: Claude Code <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01SnAJ7Z3CpVD3PRbN73QtU2

VERSION

@@ -1 +1 @@
-9.0.0-beta.9
+9.0.0-beta.10