STATE-WP-0093: per-recipient broadcast receipts and standing notices (T01-T06).

Founder approved T01 on 2026-09-22 (D2, D3, D6 as recommended).
- T02: message_receipts table; kind/expires_at/supersedes_id on
  agent_messages; migration d7e8f9a0b1c2 archives existing broadcasts,
  leaves direct messages untouched, reversible.
- T03: reader-aware mark-read (unattributed broadcast mark-read is a
  metered, deprecated no-op), delivery receipts on the scoped unread inbox,
  POST /messages/{id}/ack, news/standing kinds, expiry, supersede, broadcast
  archive no longer stamps read_at, reply writes the replier's receipt.
- T04 (state-hub part): Codex MCP reader param and acknowledge_notice;
  hub-core part handed off (message 69fc387c).
- T05: GET /messages/notices, standing_notices in /state/summary,
  dashboard standing-notices panel.
- T06: 17 new tests; full suite green.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

Assistant: claude-code
Assistant-Model: opus
Assistant-Process: 63291@bnt-lap001
Assistant-Session: 8bd77868-ca68-4f49-bb1e-d539ecc0d703

api/routers/capability_requests.py

@@ -7,7 +7,8 @@ from sqlalchemy.ext.asyncio import AsyncSession
 
 from api.database import get_session
 from api.flow_defs import assertion_result_to_dict, evaluate_transition, flow_result_to_dict
-from api.models.agent_message import AgentMessage
+from api.models.agent_message import BROADCAST, AgentMessage
+from api.services.message_receipts import NEWS_DEFAULT_TTL, utcnow
 from api.models.capability_catalog import CapabilityCatalog
 from api.models.capability_request import CapabilityRequest
 from api.models.domain import Domain
@@ -372,6 +373,10 @@ def _add_notification(
         subject=subject,
         body=body,
     )
+    if to_agent == BROADCAST:
+        # STATE-WP-0093: system broadcasts are news (seen once per reader).
+        msg.kind = "news"
+        msg.expires_at = utcnow() + NEWS_DEFAULT_TTL
     session.add(msg)