chore: strip Co-authored-by trailers in lefthook hooks

Author: Patel230

lefthook.yml

@@ -110,3 +110,18 @@ commit-msg:
           echo "  full guide: https://www.conventionalcommits.org/"
           exit 1
         fi
+
+    strip-co-authored-by:
+      run: |
+        # Strip Co-authored-by: trailers that AI tools (Claude, Cursor, etc.) add.
+        # This enforces the rule that commits list only the human author.
+        sed '/^[Cc]o-[Aa]uthored-[Bb]y:/d' "{1}" > "{1}.tmp" && mv "{1}.tmp" "{1}"
+
+# ---------------------------------------------------------------------------
+# prepare-commit-msg — strip AI co-author trailers after tools inject them.
+# ---------------------------------------------------------------------------
+prepare-commit-msg:
+  commands:
+    strip-co-authored-by:
+      run: |
+        sed '/^[Cc]o-[Aa]uthored-[Bb]y:/d' "{1}" > "{1}.tmp" && mv "{1}.tmp" "{1}"