feat(cues): client.cues.fire(send_at=...) (hosted PR #618 port)

Adds optional `send_at` kwarg to `client.cues.fire()` for per-fire
scheduling. Server-side FireRequest gained `send_at: Optional[datetime]`
in #618; the dispatcher gates on dispatch_outbox.scheduled_at.

Past timestamps are forgiving (server treats as 'fire now', idempotent —
no error for a few-ms-late caller).

Tests: 3 new (4 → 7 in TestFire). Pinned: send_at omitted from body when
default None; combines correctly with payload_override + merge_strategy.

Depends on cueapi/cueapi#618 merging to staging then prod for user-visible
behavior. PR can merge independently — sending an unknown send_at field
against an old server is silently ignored (Pydantic extra='ignore'
default on FireRequest).

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Author: mikemolinet

cueapi/resources/cues.py

@@ -225,6 +225,7 @@ def fire(
         *,
         payload_override: Optional[Dict[str, Any]] = None,
         merge_strategy: Optional[str] = None,
+        send_at: Optional[str] = None,
     ) -> Dict[str, Any]:
         """Fire an existing cue immediately, optionally overriding its payload.
 
@@ -241,6 +242,14 @@ def fire(
                 payload. "merge" (server default) shallow-merges with override
                 wins on key collisions. "replace" uses override as the final
                 payload, ignoring cue.payload.
+            send_at: Optional ISO 8601 UTC timestamp to schedule this fire for
+                the future (hosted PR #618). When set and in the future, the
+                resulting execution sits in ``pending`` until ``send_at <=
+                now()``, then enters the normal dispatch path. Past timestamps
+                are treated as "fire now" — idempotent and forgiving (no error
+                for a few-ms-late caller). Server's ``FireRequest.send_at`` is
+                ``Optional[datetime]``; passing an ISO string is fine
+                server-side.
 
         Returns:
             The execution dict (id, scheduled_for, status, etc.).
@@ -250,4 +259,6 @@ def fire(
             body["payload_override"] = payload_override
         if merge_strategy is not None:
             body["merge_strategy"] = merge_strategy
+        if send_at is not None:
+            body["send_at"] = send_at
         return self._client._post(f"/v1/cues/{cue_id}/fire", json=body)

tests/test_cues_resource.py

@@ -55,3 +55,54 @@ def test_fire_omits_merge_strategy_when_not_passed(self):
 
         sent_body = mock_client._post.call_args.kwargs["json"]
         assert "merge_strategy" not in sent_body
+
+    def test_fire_with_send_at(self):
+        # Hosted PR #618: per-fire scheduling. send_at as ISO string lands
+        # in the body unchanged.
+        mock_client = MagicMock()
+        mock_client._post.return_value = {
+            "id": "exec_test",
+            "scheduled_for": "2026-05-04T20:00:00Z",
+        }
+        resource = CuesResource(mock_client)
+
+        resource.fire("cue_abc123", send_at="2026-05-04T20:00:00Z")
+
+        mock_client._post.assert_called_once_with(
+            "/v1/cues/cue_abc123/fire",
+            json={"send_at": "2026-05-04T20:00:00Z"},
+        )
+
+    def test_fire_omits_send_at_when_not_passed(self):
+        # Pin: when send_at is None (default), the body must not include the
+        # key. Sending null adds noise to the request and may interact poorly
+        # with future Pydantic schemas.
+        mock_client = MagicMock()
+        mock_client._post.return_value = {"id": "exec_test"}
+        resource = CuesResource(mock_client)
+
+        resource.fire("cue_abc123")
+
+        sent_body = mock_client._post.call_args.kwargs["json"]
+        assert "send_at" not in sent_body
+
+    def test_fire_combines_send_at_with_payload_override(self):
+        mock_client = MagicMock()
+        mock_client._post.return_value = {"id": "exec_test"}
+        resource = CuesResource(mock_client)
+
+        resource.fire(
+            "cue_abc123",
+            payload_override={"task": "demo"},
+            merge_strategy="replace",
+            send_at="2026-05-04T22:00:00Z",
+        )
+
+        mock_client._post.assert_called_once_with(
+            "/v1/cues/cue_abc123/fire",
+            json={
+                "payload_override": {"task": "demo"},
+                "merge_strategy": "replace",
+                "send_at": "2026-05-04T22:00:00Z",
+            },
+        )