chore: update gitignore and Makefile

- Update .gitignore with node_modules and build artifacts
- Update Makefile with new targets

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

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

.gitignore

@@ -164,3 +164,10 @@ credentials/
 # Note: Keep alembic/versions/ tracked for migrations
 # alembic/versions/*.pyc is already covered by __pycache__
 .aider*
+
+# Node.js / npm
+node_modules/
+npm-debug.log*
+yarn-debug.log*
+yarn-error.log*
+package-lock.json