Add test infrastructure with coverage and DB test skipping

- Create @reviq/test-helpers package with shared test utilities
- Add describeE2E helper that auto-prefixes test names with [e2e]
- Support SKIP_DB_TESTS=1 to skip database-dependent tests
- Add unix socket support for TEST_DATABASE_URL
- Add root commands: test:unit, test:all, test:cov, test:unit:cov
- Configure bunfig.toml to exclude dist/ from coverage reports
- Clean up tsconfig.json files to remove redundant settings

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

packages/api-contract/package.json

@@ -12,7 +12,7 @@
   },
   "scripts": {
     "build": "tsc",
-    "test": "bun test",
+    "test": "bun test src/",
     "clean": "tsc --build --clean && rm -rf dist/ node_modules/ .eslintcache",
     "lint": "eslint . --cache"
   },