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/testing/test-helpers/src/test-transaction.ts

@@ -0,0 +1,60 @@
+/**
+ * Transaction-based test isolation helper
+ *
+ * Wraps test code in a transaction that auto-rollbacks, providing
+ * fast test isolation without truncating tables between tests.
+ */
+
+import type { Database } from "@reviq/db-schema";
+import type { Kysely } from "kysely";
+
+/**
+ * Signal used to trigger transaction rollback after test completes
+ */
+class RollbackSignal extends Error {
+  constructor() {
+    super("RollbackSignal");
+    this.name = "RollbackSignal";
+  }
+}
+
+/**
+ * Runs a test function inside a transaction that auto-rollbacks.
+ *
+ * The transaction implements the same interface as Kysely<Database>,
+ * so it can be passed to context builders and used for all queries.
+ * After the test completes, the transaction is rolled back, providing
+ * instant cleanup without truncating tables.
+ *
+ * @example
+ * ```typescript
+ * test("creates user", async () => {
+ *   await withTestTransaction(getSharedDb(), async (db) => {
+ *     const user = await createTestUser(db, { email: "test@example.com" });
+ *     const ctx = createAPIContext({ db });
+ *     // ... test code
+ *   }); // Auto-rollback here
+ * });
+ * ```
+ */
+export async function withTestTransaction<T>(
+  db: Kysely<Database>,
+  testFn: (trx: Kysely<Database>) => Promise<T>,
+): Promise<T | undefined> {
+  let result: T | undefined;
+
+  try {
+    await db.transaction().execute(async (trx) => {
+      result = await testFn(trx);
+      // Force rollback by throwing after test completes successfully
+      throw new RollbackSignal();
+    });
+  } catch (e) {
+    // Swallow the rollback signal - this is expected behavior
+    if (!(e instanceof RollbackSignal)) {
+      throw e;
+    }
+  }
+
+  return result;
+}