chore: skip QA checks in pre-commit when no Rust files changed

Only run cargo make qa when .rs, Cargo.toml, or Cargo.lock files
are staged for commit. This speeds up commits for non-Rust changes.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: bordeux

.husky/pre-commit

@@ -7,5 +7,14 @@ if [ -f .git/MERGE_HEAD ]; then
   exit 0
 fi
 
-# Run QA checks for regular commits
+# Check if any Rust files are staged for commit
+RUST_FILES=$(git diff --cached --name-only --diff-filter=ACMR | grep -E '\.(rs)$|^Cargo\.(toml|lock)$' || true)
+
+if [ -z "$RUST_FILES" ]; then
+  echo "No Rust files changed, skipping cargo make qa"
+  exit 0
+fi
+
+# Run QA checks for commits with Rust changes
+echo "Rust files changed, running cargo make qa..."
 cargo make qa