Use git hooks for commit attribution

Co-authored-by: Codex <noreply@openai.com>

codex-rs/core/config.schema.json

@@ -1778,6 +1778,7 @@
       "description": "Preferred backend for storing CLI auth credentials. file (default): Use a file in the Codex home directory. keyring: Use an OS-specific keyring service. auto: Use the keyring if available, otherwise use a file."
     },
     "commit_attribution": {
+      "default": null,
       "description": "Optional commit attribution text for commit message co-author trailers.\n\nSet to an empty string to disable automatic commit attribution.",
       "type": "string"
     },