Add prettier formatting and CI validation checks

- Add prettier with consistent formatting config
- Add format and format:check npm scripts
- Add prettier pre-commit hook
- Add validation and formatting checks to CI workflow
- Reformat all TypeScript and JSON files

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

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

tsconfig.json

@@ -13,4 +13,4 @@
   },
   "include": ["src/**/*"],
   "exclude": ["node_modules"]
-}
+}