Add READMEs for remaining packages

- db-schema: Database schema types from kysely-codegen
- db: Database client and helper functions
- testing: Overview of testing packages
- test-helpers: Database testing utilities
- virtual-authenticator: WebAuthn virtual authenticator

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

packages/testing/test-helpers/README.md

@@ -0,0 +1,52 @@
+# @reviq/test-helpers
+
+Database testing utilities for integration and e2e tests.
+
+## Usage
+
+```typescript
+import {
+  describeE2E,
+  createTestDb,
+  withTestTransaction,
+  createTestUser,
+} from "@reviq/test-helpers";
+
+describeE2E("My API tests", () => {
+  it("should create a user", async () => {
+    await withTestTransaction(async (trx) => {
+      const user = await createTestUser(trx, {
+        email: "test@example.com",
+      });
+      expect(user.id).toBeDefined();
+    });
+  });
+});
+```
+
+## Exports
+
+### Test Setup
+- `describeE2E(name, fn)` - Wrapper for describe() that skips when `SKIP_DB_TESTS=1`
+- `SKIP_DB_TESTS` - Boolean indicating if db tests should be skipped
+
+### Database Utilities
+- `createTestDb()` - Create an isolated test database
+- `destroyTestDb(db)` - Destroy a test database
+- `getSharedDb()` - Get the shared test database instance
+- `destroySharedDb()` - Destroy the shared database
+- `initTestDb()` - Initialize the test database
+- `runMigrations(url)` - Run database migrations
+- `truncateAllTables(db)` - Clear all data from tables
+- `getTestDatabaseUrl()` - Get the test database connection URL
+
+### Transaction Helpers
+- `withTestTransaction(fn)` - Run a function in a rolled-back transaction
+
+### Fixtures
+- `createTestUser(trx, opts)` - Create a test user
+
+### Constants
+- `TEST_RP` - Test relying party configuration for WebAuthn
+- `DEFAULT_TEST_AAGUID` - Default AAGUID for virtual authenticator
+- `KNOWN_AAGUIDS` - Map of known authenticator AAGUIDs