Remove legacy release recording lambdas

[gontzess]

Why

Release metadata is now recorded through the connector registry API. The older Lambda recording paths still wrote to deprecated release tables and kept the shared workflow coupled to systems that are no longer the source of truth.

The registry API also expects Lambda image metadata when a connector publishes a Lambda image. Removing the old Lambda registry job means the release manifest must carry that metadata directly.

What this changes

• Removes the dist release Lambda invocation from the release workflow.
• Removes the per-connector record-lambda-registry job.
• Records Lambda image metadata as lambda-arm64 in the release manifest.
• Adds GoReleaser docker_digest output for Lambda builds so the workflow can capture the pushed Lambda image digest.
• Renames the manifest/checksum publication job from record-connector-registry to publish-release-manifest.
• Makes record-registry-api depend on the manifest publication job only.
• Keeps publish-release-manifest and record-registry-api separate so dist publication and registry API ingest remain distinct failure points.
• Updates the release workflow docs and diagram.

Validation

• go test ./...
• git diff --check
• make docs
• YAML parse for .github/workflows/release.yaml
• Live release v0.1.122-test.5: Lambda-only, passed through record-registry-api
• Live release v0.1.122-test.6: Docker plus Lambda, passed through record-registry-api
• Live release v0.1.122-test.7: renamed publish-release-manifest, record-registry-api, and verify-release passed