feat(canvas): Agent 审批 - 节点直接生成时自动关闭同节点的待审批任务

用户在画布节点上直接提交生成后，同画布 Agent 对该节点等待中的 generate_media 审批关闭为 superseded_by_node，Agent 带着「用户已手动提交」的结果继续，不重复提交、不扣费。审批卡片识别目标节点正在生成时禁用「同意执行」并提示原因。

web/src/lib/canvas/agent-media-approval.ts

@@ -1,4 +1,6 @@
 import type { AgentMediaSettings } from "@/services/api/agent";
+import { isCanvasNodeGenerating } from "@/lib/canvas/canvas-node-task-state";
+import type { CanvasNodeData } from "@/types/canvas";
 import { logicalModelIDForConfig, modelOptionName, resolveModelChannel, selectableModelsByCapability, type AiConfig } from "@/stores/use-config-store";
 
 export type AgentImageApproval = AgentMediaSettings & { prompt: string; referenceNodeIds: string[] };
@@ -43,3 +45,30 @@ export function agentApprovalModelSelection(config: AiConfig, model: string): Pi
     if (channel.scope !== "system") throw new Error("Agent 生成仅支持平台模型");
     return { channelId: channel.id, channelModelKey: modelOptionName(model) };
 }
+
+/** 后端在用户直接从节点提交生成时写入的审批决定（与 Go 侧 cloudAgentApprovalSuperseded 一致）。 */
+export const AGENT_APPROVAL_SUPERSEDED_BY_NODE = "superseded_by_node";
+
+/** 待审批 generate_media 的目标节点；其他工具返回空串。 */
+export function agentMediaApprovalTargetNodeId(detail: Record<string, unknown>): string {
+    const call = detail.call as { function?: { name?: string; arguments?: unknown } } | undefined;
+    if ((call?.function?.name || detail.toolName) !== "generate_media") return "";
+    const raw = call?.function?.arguments ?? detail.arguments;
+    try {
+        const args = typeof raw === "string" ? JSON.parse(raw) : raw;
+        return args && typeof args.nodeId === "string" ? args.nodeId.trim() : "";
+    } catch {
+        return "";
+    }
+}
+
+/**
+ * 审批的目标节点已经在画布上生成中（用户直接点了节点的生成）。
+ * 后端会随后推送 superseded 决定；这里只负责在事件到达前挡住重复点击“同意执行”。
+ */
+export function agentApprovalTargetGenerating(detail: Record<string, unknown>, nodes: readonly CanvasNodeData[] | undefined, runningNodeId?: string | null): CanvasNodeData | undefined {
+    const nodeId = agentMediaApprovalTargetNodeId(detail);
+    if (!nodeId || !nodes) return undefined;
+    const target = nodes.find((node) => node.id === nodeId);
+    return target && isCanvasNodeGenerating(target, runningNodeId) ? target : undefined;
+}