docs(client): preserve opaque context fallback

packages/client/ui-conversation/src/client/contract/context-provenance.ts

@@ -23,5 +23,9 @@ export interface ContextProvenanceView {
   label: string | null
 }
 
-/** One durable context form this UI version knows how to present. */
+/**
+ * One durable context form this UI version knows how to present. Target
+ * projections map absent or unknown forms to their opaque presentation so
+ * logs written by older, newer, or foreign producers remain visible.
+ */
 export type KnownContextForm = 'instructions' | 'catalog' | 'snapshot' | 'notice' | 'relay' | 'recall'