Reauthorize cached previews through immutable indexed evidence IDs

When a Postgres projection is append-only and cached previews require fresh authorization, retain exact representative evidence IDs in private immutable server metadata. Recheck those IDs through primary-key lookups under current RLS, together with the owning person, session and excerpt-source permissions. Avoid searching session history merely to prove visibility: that work can grow as the timeline advances and turn healthy cached responses into timeout fallbacks. This approach narrows grants rather than expanding them. Its availability guarantee depends on preserving evidence IDs; deleting and rebuilding projections requires cache invalidation. Per-record policies may require checking every referenced record instead of one representative per session.

Applies when: Cached product views depend on fresh access checks over immutable Postgres projections. Keywords: Postgres RLS cache authorization immutable projection primary key latency previews