refactor: extract prepare-commit-msg hook to separate script file

- Move commitment hook logic from inline lefthook.yml to dedicated .lefthook/prepare-commit-msg/commitment.sh
- Preserve hook behavior: only run for regular commits (check if $2 is empty)
- Simplify lefthook.yml configuration using scripts runner instead of inline command

🤖 Generated with Claude via commitment

Author: arittr

.lefthook/prepare-commit-msg/commitment.sh

@@ -0,0 +1,8 @@
+#!/bin/sh
+# Commitment hook for prepare-commit-msg
+# Arguments: $1 = commit message file, $2 = commit source (empty for regular commits)
+
+# Only run for regular commits (no commit source means git commit without -m)
+if [ -z "$2" ]; then
+  ./dist/cli.js --message-only > "$1"
+fi

lefthook.yml

@@ -14,8 +14,6 @@ prepare-commit-msg:
   skip:
     - merge
     - rebase
-  commands:
-    commitment:
-      # Only run for regular commits (not merge, squash, or when message specified)
-      # {1} is the commit message file, {2} is the commit source
-      run: '[ -z "{2}" ] && ./dist/cli.js --message-only > {1} || true'
+  scripts:
+    "commitment.sh":
+      runner: sh