2.12.1

Fixes service-mode startup for Laravel applications using PHP SDK 3. Waterline now accepts stable SDK 3.x alongside the existing SDK 2 stable and cancellation-release-candidate paths. Unsupported majors, development versions and historical prereleases remain rejected. Embedded mode keeps the SDK optional.

The observer uses the published Client API. Source qualification passes 87 tests and 935 assertions on each normal SDK 2.4.0 and 3.1.0 profile. Real Laravel startup, UI and running/completed API calls also pass with each SDK generation against published Server 2.10.0. The standalone image retains its existing locked SDK selection.

Normal source qualification includes the supported Laravel matrix, complete database scopes, service-image smoke, production frontend build and Sonar. No OpenTelemetry dependency, native/Cloud adoption or worker-registration API change is introduced.

Fixes #223, implemented in #224, and unblocks the combined Sample tracing consumer. The normal publisher passes, including the exact published-image smoke. durableworkflow/waterline:2.12.1 resolves to index sha256:b55484dbaae890f929cf2bf2d639d4e3a77bcfd7f1d1f4455662588f99299f08 from source 4d750dcd63aa062977fb895c8ac317bdac9c18d8. All 163 bundled production files match that source; the image retains SDK 2.4.0 and has no OpenTelemetry API dependency. Normal Packagist selects the same immutable Waterline source. The installed Sample consumer passes all 31 focused contracts and 293 assertions with SDK 3.1.0 and Core 2.9.0. Full downstream journeys and the post-release manifest selections remain tracked in the owning issues.