fix(multiplayer): recover queue revision conflicts

Game/scripts/control_plane_client.gd

@@ -298,6 +298,10 @@ static func is_retryable_mutation_response(response_code: int) -> bool:
 	return response_code == 0 or response_code == HTTPClient.RESPONSE_REQUEST_TIMEOUT or response_code == HTTPClient.RESPONSE_TOO_MANY_REQUESTS or response_code >= 500
 
 
+static func should_recover_queue_after_conflict(operation: String, response_code: int, ticket_id: String) -> bool:
+	return response_code == HTTPClient.RESPONSE_CONFLICT and operation in ["queue_heartbeat", "queue_cancel"] and not ticket_id.is_empty()
+
+
 static func normalize_ticket(payload: Dictionary) -> Dictionary:
 	var result := payload.duplicate(true)
 	if result.has("enqueued_at") and result["enqueued_at"] is String:
@@ -373,6 +377,7 @@ func _on_request_completed(result: HTTPRequest.Result, response_code: int, _head
 		_last_mutation_retryable = _last_mutation.get("operation", "") == operation and is_retryable_mutation_response(response_code)
 		var detail := String(parsed.get("error", "request rejected"))
 		var recover_proposal_after_conflict := response_code == HTTPClient.RESPONSE_CONFLICT and (operation == "proposal_accept" or operation == "proposal_decline") and not state.proposal_id.is_empty()
+		var recover_queue_after_conflict := should_recover_queue_after_conflict(operation, response_code, state.ticket_id)
 		if response_code == HTTPClient.RESPONSE_UNAUTHORIZED:
 			access_token = ""
 			auth_expired = true
@@ -396,6 +401,9 @@ func _on_request_completed(result: HTTPRequest.Result, response_code: int, _head
 		if recover_proposal_after_conflict:
 			_pending_resync_resource_id = state.proposal_id
 			call_deferred("_run_pending_resync")
+		if recover_queue_after_conflict:
+			_pending_resync_resource_id = state.ticket_id
+			call_deferred("_run_pending_resync")
 		return
 	var payload: Dictionary = parsed
 	_last_mutation_retryable = false

Game/tests/cases/test_control_plane_client.gd

@@ -99,6 +99,14 @@ func test_retryable_mutation_policy_only_retries_safe_failures() -> void:
 	assert_true(not ControlPlaneClient.is_retryable_mutation_response(409), "revision/idempotency conflict is not blindly replayed")
 
 
+func test_queue_revision_conflicts_schedule_authoritative_recovery() -> void:
+	assert_true(ControlPlaneClient.should_recover_queue_after_conflict("queue_heartbeat", 409, "ticket-1"), "stale heartbeat recovers the queue ticket")
+	assert_true(ControlPlaneClient.should_recover_queue_after_conflict("queue_cancel", 409, "ticket-1"), "stale cancellation recovers the queue ticket")
+	assert_true(not ControlPlaneClient.should_recover_queue_after_conflict("queue_create", 409, "ticket-1"), "create conflict uses its own idempotency path")
+	assert_true(not ControlPlaneClient.should_recover_queue_after_conflict("queue_heartbeat", 503, "ticket-1"), "transient outage remains retryable instead of being treated as a revision conflict")
+	assert_true(not ControlPlaneClient.should_recover_queue_after_conflict("queue_cancel", 409, ""), "missing ticket cannot trigger recovery")
+
+
 func test_assignment_endpoint_split_never_accepts_url_or_bad_port() -> void:
 	var endpoint := ControlPlaneClient._split_assignment_endpoint("127.0.0.1:31001")
 	assert_eq(endpoint["host"], "127.0.0.1", "assignment host is separated from the port")

multiplayer-next.md

@@ -1558,3 +1558,5 @@ All client resync entry points now apply the open-proposal boundary: a terminal
 Ticket projections now validate playlist metadata on every update, rejecting unknown values before either phase or playlist state can mutate. An adversarial higher-revision update test covers this boundary.
 
 Client sessions now fail closed at the expiry boundary and proactively clear credentials before reconnects or authenticated requests. Boundary and malformed-expiry tests cover the lifecycle guard.
+
+Queue heartbeat and cancellation revision conflicts now schedule the same authoritative ticket recovery as proposal conflicts, preventing stale client actions from leaving the visible queue state unresolved. Adversarial operation/status/identity coverage is included.