InMemoryPersistenceProvider, InMemoryLockProvider, InMemoryQueueProvider,
InMemoryLifecyclePublisher behind test-support feature flag.
Shared test suite macros: persistence_suite!, lock_suite!, queue_suite!
that run the same tests against any provider implementation.
Workspace with 6 crates: wfe-core, wfe-sqlite, wfe-postgres,
wfe-opensearch, wfe-valkey, and wfe (umbrella). Nextest profiles
for default, integration, and CI. Docker compose for PostgreSQL,
Valkey, and OpenSearch integration tests.