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>

package.json

@@ -16,6 +16,10 @@
     "typecheck": "turbo typecheck",
     "clean": "turbo clean",
     "test": "turbo test",
+    "test:unit": "SKIP_DB_TESTS=1 turbo test",
+    "test:all": "turbo test",
+    "test:cov": "bun test --coverage",
+    "test:unit:cov": "SKIP_DB_TESTS=1 bun test --coverage",
     "db:codegen": "bun run --cwd packages/db-schema generate"
   },
   "devDependencies": {