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>

.github/workflows/pr-check.yml

@@ -0,0 +1,34 @@
+name: PR Check
+
+on:
+  pull_request:
+    branches: [main, dev-*]
+
+jobs:
+  lint-and-build:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+
+      - name: Setup Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: "20"
+          cache: "npm"
+
+      - name: Install dependencies
+        run: npm ci
+
+      - name: Run ESLint
+        run: npx eslint .
+
+      - name: Run Prettier check
+        run: npx prettier --check .
+
+      - name: Type check
+        run: npx tsc --noEmit
+
+      - name: Build
+        run: npm run build