Mentions ride the existing event-driven inbox — no chat parsing in the kernel:
- send() carries an OPAQUE mentions[] (userIds) into the message event; the kernel
never parses "@". The app supplies the notify-list.
- InboxProjector fans out a MENTION inbox item (new generic inbox kind) to each
mentioned *participant* (never the sender), idempotent per source message; reading
the thread resolves the reader's MENTION + NEEDS_REPLY items to DONE.
- New MENTION value in the generic IiosInboxItemKind taxonomy (migration).
Pins/saves reuse the annotation primitive; new generic query powers a Saved list:
- MessageService.listMyAnnotated(principal, type) + GET /v1/threads/my-annotations
returns the caller's annotated messages (type "save") with thread context.
Tests: 182 pass (+4: mention fan-out, resolve-on-read, saved query, opaque mentions).
Verified live: mention→inbox delivery, read→resolve, pin/save persistence.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
