fix(agent): 输入草稿按会话保留,切换会话、关抽屉不丢

会话面板与新对话输入框的草稿原来是组件内状态,切到别的会话或 Esc 关抽屉就没了。
改为按会话(以及列表页 / 抽屉两处新对话)分键记在模块里,发送成功后清掉。

Co-Authored-By: Claude Opus 5.5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01Cxwgnn2pbzQ7rXv3rq7fei

apps/web/app/routes/console/agent.tsx

@@ -2,7 +2,13 @@ import { FlaskConical } from "lucide-react";
 import { useNavigate } from "react-router";
 import { toast } from "sonner";
 import { agentMockEnabled, useCreateAgentRun } from "~/api/agent.ts";
-import { agentRunHref, pageListMemory, usePageListGroup } from "~/components/agent/agent-nav.ts";
+import {
+  agentRunHref,
+  DRAFT_PAGE_GOAL,
+  pageListMemory,
+  usePageListGroup,
+  writeDraft,
+} from "~/components/agent/agent-nav.ts";
 import { GoalComposer } from "~/components/agent/agent-run-panel.tsx";
 import { AgentSessionList } from "~/components/agent/agent-session-list.tsx";
 import { quickGoalsFor } from "~/components/agent/quick-goals.ts";
@@ -43,11 +49,15 @@ export default function AgentPage() {
           <GoalComposer
             pending={create.isPending}
             suggestions={quickGoalsFor("/console/agent")}
+            draftKey={DRAFT_PAGE_GOAL}
             onSubmit={(goal, opts) =>
               create.mutate(
                 { goal, ...opts },
                 {
-                  onSuccess: (run) => navigate(agentRunHref(run.id, mock)),
+                  onSuccess: (run) => {
+                    writeDraft(DRAFT_PAGE_GOAL, "");
+                    navigate(agentRunHref(run.id, mock));
+                  },
                   onError: (e) => toast.error(errorMessage(e)),
                 },
               )