fix: add package-lock.json for CI reproducibility

- Remove package-lock.json from .gitignore
- Add typescript-eslint and @eslint/js dependencies
- Include lock file for npm ci to work in GitHub Actions

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

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

Author: daichi-pepk

.gitignore

@@ -27,7 +27,6 @@ npm-debug.log*
 .env
 .env.local
 
-# Package manager
-package-lock.json
+# Package manager (keep package-lock.json for CI reproducibility)
 yarn.lock
 pnpm-lock.yaml