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>

.pre-commit-config.yaml

@@ -22,3 +22,10 @@ repos:
         language: system
         pass_filenames: false
         files: ^src/config/
+
+      - id: prettier
+        name: Prettier formatting
+        entry: npx prettier --write --ignore-unknown
+        language: system
+        types: [text]
+        files: \.(ts|tsx|js|jsx|json|md)$