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>

.commitlintrc.json

@@ -0,0 +1,21 @@
+{
+  "extends": ["@commitlint/config-conventional"],
+  "rules": {
+    "type-enum": [
+      2,
+      "always",
+      [
+        "feat",
+        "fix",
+        "docs",
+        "style",
+        "refactor",
+        "perf",
+        "test",
+        "chore",
+        "revert"
+      ]
+    ],
+    "subject-case": [0]
+  }
+}