Why: The three pinned reds define EXT-8 slice 2 - adapter-granted cross-owner knowledge must be retrievable, conversation cards must stay out of public project streams when the host opts out, and project-stream subscription must honor the authorizer.
Evidence: TestConvCardMirrorSwitch, TestSharedKnowledgeRetrieval, TestProjectSSEScopeGate green; go test ./... 32/32 packages ok; rows follow on the task card.
Impact: store gains predicate-based SearchKnowledgeShared (FTS/LIKE shared variants + PG); searchKnowledge appends adapter-authorized hits; cardsvc emit gate (no publish = no persistence = clean replay); events project scope consults authorizeSharedProject. Default behavior unchanged everywhere.
Refs: EXT-8/EXT-12 proposals; red run at surface commit.
Why: Knowledge retrieval cross-owner and conversation-card mirroring are the registered EXT-8 slice-2 items; the fields/wiring land with the acceptance reds pinned first.
Evidence: mirror red (project channel still emitted with switch off); shared-retrieval red (grant yields 0 hits); SSE-scope red (grant yields non-200); rows follow on the task card.
Impact: Options.DisableConvCardMirror passthrough (extension/link/app); cardsvc.MirrorConvCards (default true = current behavior); SurfaceVersion 2.3.0-experimental. Behavior unchanged.
Refs: EXT-8/EXT-12 proposals; task card.