fix: keep cancelled turns as interrupted instead of merging into the next request

- Build runtime history per turn: a cancelled or failed reply keeps its partial
  text plus an interruption marker (or a marker-only placeholder), so its user
  message is never left unanswered and merged into the next request.
- Use the same history for send, manual compaction and Main compact validation.
- OpenCode: keep a cancelled prompt in the reused native session and prefix the
  next turn with a one-time synthetic interruption notice; failed prompts are
  still removed.
- Add an opt-in DeepSeek live test covering direct model and OpenCode.

src/renderer/src/App.test.tsx

@@ -23,6 +23,7 @@ import {
   type ApplicationSettings,
 } from "../../shared/application-settings-contracts";
 import type { GlobalShortcutSettingsSnapshot } from "../../shared/shortcut";
+import { cancelledResponseMarker } from "../../shared/runtime-history";
 import type { TerminalSnapshot } from "../../shared/terminal-contracts";
 import type { RuntimeNativeClientApi } from "./RuntimeNativeClientActions";
 import { loadBrandingPreferences, saveBrandingPreferences } from "./branding";
@@ -6041,6 +6042,32 @@ describe("App", () => {
     ]);
   });
 
+  it("sends a cancelled turn as interrupted instead of an unanswered user message", async () => {
+    render(<App />);
+    fireEvent.change(screen.getByLabelText("向 GoodBuddy 提问"), {
+      target: { value: "First question" },
+    });
+    fireEvent.click(await screen.findByLabelText("发送"));
+    await waitFor(() => expect(run).toHaveBeenCalledOnce());
+    const requestId = run.mock.calls[0]![0].requestId;
+    act(() => {
+      agentListener?.({ requestId, type: "text", delta: "Partial reply" });
+      agentListener?.({ requestId, type: "error", status: "cancelled", message: "请求已取消" });
+    });
+    fireEvent.change(screen.getByLabelText("向 GoodBuddy 提问"), {
+      target: { value: "New question" },
+    });
+    await waitFor(() => expect(screen.getByLabelText("发送")).toBeEnabled());
+    fireEvent.click(screen.getByLabelText("发送"));
+    await waitFor(() => expect(run).toHaveBeenCalledTimes(2));
+    const history = run.mock.calls[1]?.[0].history ?? [];
+    expect(history.slice(-2)).toEqual([
+      { role: "user", content: "First question" },
+      { role: "assistant", content: `Partial reply\n\n${cancelledResponseMarker}` },
+    ]);
+    expect(run.mock.calls[1]?.[0].historyMessageIds).toHaveLength(history.length);
+  });
+
   it("keeps a tool failure in details and hides retry after continuing", async () => {
     render(<App />);
 

src/renderer/src/App.tsx

@@ -13,6 +13,7 @@ import { PendingDocumentImports } from './PendingDocumentImports';
 import { AttachmentCapabilityNotice } from './AttachmentCapabilityNotice';
 import { DocumentConversationContext } from './DocumentConversationContext';
 import { maximumAttachmentsPerMessage } from '../../shared/attachment-limits';
+import { buildRuntimeHistory } from '../../shared/runtime-history';
 import {
   ApplicationAvailability,
   ApplicationCenter,
@@ -7091,9 +7092,7 @@ function App(): React.JSX.Element {
       8,
     );
     const historySnapshot = conversationSnapshot.messages;
-    const retainedHistorySnapshot = historySnapshot.filter(
-        (message) => message.state === "complete" && message.content.trim(),
-      );
+    const retainedHistorySnapshot = buildRuntimeHistory(historySnapshot);
     const projectIdSnapshot = queuedInput
       ? queuedInput.projectId
       : activeProjectId || undefined;
@@ -7435,9 +7434,7 @@ function App(): React.JSX.Element {
       notify({ tone: "error", message: t("notices.remoteConversationRefreshFailed") });
       return;
     }
-    const history = completeConversation.messages.filter(
-        (message) => message.state === "complete" && message.content.trim(),
-      );
+    const history = buildRuntimeHistory(completeConversation.messages);
     if (history.length < 2) {
       notify({
         tone: "info",

src/renderer/src/message-terminal-status.ts

@@ -1,11 +1 @@
-import type { ConversationMessage } from '../../shared/assistant-contracts'
-
-export function isCancelledMessage(message: Pick<ConversationMessage,
-  'state' | 'terminalStatus' | 'status'>): boolean {
-  if (message.state !== 'error') return false
-  if (message.terminalStatus !== undefined) return message.terminalStatus === 'cancelled'
-  // Released snapshots lack terminalStatus. Only recognize exact old labels;
-  // every new terminal event supplies the structured value above.
-  return message.status === '请求已取消' || message.status === '已取消' ||
-    message.status === '远端 Runtime 请求已取消'
-}
+export { isCancelledMessage } from '../../shared/runtime-history'