fix(awooop): write outbound sent timestamp as parameter

apps/api/src/services/channel_hub.py

@@ -489,6 +489,7 @@ async def record_outbound_message(
     source_envelope_json = json.dumps(envelope, ensure_ascii=False, default=str)
 
     actual_status = "shadow" if is_shadow else send_status
+    sent_at = datetime.now(UTC) if actual_status == "sent" else None
 
     await ensure_completed_shadow_run(
         db,
@@ -522,8 +523,7 @@ async def record_outbound_message(
                 :content_hash, :content_preview, :content_redacted,
                 :redaction_version, CAST(:source_envelope AS jsonb),
                 :provider_message_id,
-                :send_status, NOW(),
-                CASE WHEN CAST(:send_status AS text) = 'sent' THEN NOW() ELSE NULL END,
+                :send_status, NOW(), :sent_at,
                 :triggered_by_state, :waiting_since
             )
             RETURNING message_id
@@ -542,6 +542,7 @@ async def record_outbound_message(
             "source_envelope": source_envelope_json,
             "provider_message_id": provider_message_id,
             "send_status": actual_status,
+            "sent_at": sent_at,
             "triggered_by_state": triggered_by_state,
             "waiting_since": waiting_since,
         },