feat(platform): deliver metadata fabric lineage

[zhouning]

Summary

• add a tenant-scoped Metadata Fabric lineage outbox with forced RLS, bounded claims, lease recovery, retry and receipt state
• require the exact M3-3 binding, authorized apply plan and complete M3-1 source plan before enqueue
• send canonical OpenLineage JSON with stable idempotency, delivery and event fingerprint headers
• prove commit-then-failed-ack recovery over a real loopback HTTP connection: 503, retry, duplicate 200, two requests and one receiver acceptance
• add ADR-050, retained evidence, runtime truth, roadmap, system-of-record and CI coverage

Verification

• required platform suite: 613 passed
• PostgreSQL integration suites: 5 passed
• focused contract and gateway tests: 41 passed
• platform truth and migration tests: 25 passed
• frontend production build: passed
• migration catalog: 99 migrations, valid
• final local PostgreSQL and HTTP rehearsal: verified

Claim boundary

This proves local wire delivery with at-least-once transport and receiver idempotency. It does not prove network exactly-once, protected OIDC/TLS, an authenticated production receiver, durable catalog conformance, production ingestion or production readiness.

Stack

This M3-4 PR is based on feat/ar1-metadata-fabric-binding-ledger so its diff contains only the OpenLineage delivery capability. It must not be merged automatically.