cleanup phases 6

archive/build-chain/contracts/domains/messaging.md

@@ -0,0 +1,30 @@
+# messaging — MERGED into `docs/integration/domains/`
+
+> ⛔ **This headerless 851-byte fragment silently amended
+> [`messaging-notifications-admin.md`](messaging-notifications-admin.md) next to it** — two live files
+> describing one domain, which is contradiction **C-8**.
+>
+> Both are superseded. Phase 2 split the merged content three ways, along the client's actual domain
+> boundaries:
+>
+> | Content | Now |
+> | --- | --- |
+> | Tickets, threads, messages, `is_internal`, the staff queue | [`docs/integration/domains/tickets.md`](../../../docs/integration/domains/tickets.md) |
+> | The notification feed and unread badge | [`docs/integration/domains/notifications.md`](../../../docs/integration/domains/notifications.md) |
+> | Platform config, holidays, audit, support alerts | [`docs/integration/domains/admin.md`](../../../docs/integration/domains/admin.md) |
+>
+> Every REQ-028 amendment below is folded into `tickets.md` as current fact, not as a change log. Phase 6
+> archives this folder; until then, read it as a record.
+
+---
+
+## Refinement phase 3 additions (REQ-028)
+
+- **`TicketSummaryDto`** gains `lastMessageAt` (last non-internal activity) + `unreadCount` (the caller's unread
+  non-internal messages from others; 0 on the admin queue). Unread is computed against the participant's
+  `last_read_at`, **stamped when the participant fetches the user-facing thread**.
+- **`GET /tickets`** gains a `bookingId` query filter (jump to a booking's coordination ticket).
+- **`POST /tickets/{id}/messages`** accepts an optional `clientMessageId` — a retried send with the same key is
+  deduplicated (returns the original) and the key is echoed on `PostMessageResult`.
+- **Message author = role label, not a name** (confirmed intentional, privacy): the DTO carries `senderId`; the
+  client derives the author label from the participant role. No raw identity/name is exposed.