chore: add engineering improvements

- Configure Prettier with unified code style rules
- Add husky + lint-staged for automated pre-commit checks
- Add commitlint to enforce conventional commit messages
- Add PR check workflow for CI automation
- Auto-format all files with Prettier
- Fix TypeScript any types in field-crypto.ts

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

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

.prettierrc

@@ -1 +1,9 @@
-{}
+{
+  "semi": true,
+  "singleQuote": false,
+  "tabWidth": 2,
+  "trailingComma": "all",
+  "printWidth": 80,
+  "arrowParens": "always",
+  "endOfLine": "lf"
+}