Building a Six-Tier Syndication Mesh on Postgres

Tier model\n\nTiers 1-3 are contractual partners with bearer credentials. Tiers 4-6 are open consumption.\n\n## Policy shape\n\nOne public policy scoped to published rows, one authenticated policy for editorial. The tier gate lives in the request handler, not the database.\n\n## Logging\n\nEvery request writes status, latency and a SHA-256 payload hash so partners can verify integrity without a second call.