fix(run): stop the terminal wheel from typing arrow keys, re-attach dropped sockets

Three separate reasons the Workspace terminal looked unscrollable:

- xterm falls back, on an alt-screen buffer whose program has not enabled
  mouse tracking, to translating each wheel notch into a cursor-key press.
  Inside a `claude` pane that reads as arrow up/down, so scrolling walked the
  prompt history. A custom wheel handler returning false suppresses only that
  emulation branch; real mouse reports come from a separate listener xterm
  registers when the program does request wheel events.
- TerminalView never reconnected, so a server restart left the pane frozen on
  its last painted frame — still live-looking, but swallowing every keystroke
  and mouse report. It now re-attaches 1.5s after an unexpected close and
  stops only on the server's `exit` frame; tmux keeps the session, so the
  re-attach repaints in full.
- tmux repaints the whole pane, so xterm's own scrollback is always empty and
  its viewport scrollbar renders as a groove with no thumb that cannot move.
  Hidden, since scrolling there goes through mouse reports, not the DOM.

client/src/components/run/__tests__/TerminalView.test.tsx

@@ -2,7 +2,8 @@
  * @file TerminalView.test.tsx
  * @description Tests for the xterm.js-backed terminal view: verifies it opens
  * a WS connection to the right URL, writes incoming binary frames to the
- * mocked terminal, and forwards typed input as outgoing binary frames.
+ * mocked terminal, forwards typed input as outgoing binary frames, and
+ * re-attaches after the socket drops (server restart) but not after `exit`.
  * @author Nguyễn Ngọc Trí Vĩ <vinnt@smartgift.vn>
  */
 import { describe, it, expect, vi, beforeEach, afterEach } from "vitest";
@@ -13,6 +14,7 @@ const writeMock = vi.fn();
 const onDataHandlers: Array<(d: string) => void> = [];
 const openMock = vi.fn();
 const disposeMock = vi.fn();
+const wheelHandlerMock = vi.fn();
 
 vi.mock("@xterm/xterm", () => ({
   Terminal: vi.fn().mockImplementation(() => ({
@@ -24,6 +26,7 @@ vi.mock("@xterm/xterm", () => ({
     },
     dispose: disposeMock,
     loadAddon: vi.fn(),
+    attachCustomWheelEventHandler: wheelHandlerMock,
   })),
 }));
 vi.mock("@xterm/addon-fit", () => ({
@@ -56,6 +59,7 @@ describe("TerminalView", () => {
     MockWebSocket.instances = [];
     onDataHandlers.length = 0;
     writeMock.mockClear();
+    wheelHandlerMock.mockClear();
     openMock.mockClear();
   });
 
@@ -90,4 +94,32 @@ describe("TerminalView", () => {
     onDataHandlers[0]!("ls -la\r");
     expect(ws.sent).toEqual(["ls -la\r"]);
   });
+
+  it("swallows wheel events xterm would otherwise turn into arrow keys", () => {
+    render(<TerminalView runId="ccam-lane-1" wsBaseUrl="ws://localhost:4820" />);
+    expect(wheelHandlerMock).toHaveBeenCalledTimes(1);
+    // false = xterm skips its alt-screen wheel→cursor-key emulation, which in a
+    // claude pane would walk the prompt history instead of scrolling.
+    expect(wheelHandlerMock.mock.calls[0]![0]!(new Event("wheel"))).toBe(false);
+  });
+
+  it("re-attaches after the socket drops (a server restart must not freeze the pane)", () => {
+    vi.useFakeTimers();
+    render(<TerminalView runId="ccam-lane-1" wsBaseUrl="ws://localhost:4820" />);
+    MockWebSocket.instances[0]!.close();
+    vi.advanceTimersByTime(1600);
+    expect(MockWebSocket.instances).toHaveLength(2);
+    vi.useRealTimers();
+  });
+
+  it("does not re-attach once the server reported the pane exited", () => {
+    vi.useFakeTimers();
+    render(<TerminalView runId="ccam-lane-1" wsBaseUrl="ws://localhost:4820" />);
+    const ws = MockWebSocket.instances[0]!;
+    ws.onmessage?.({ data: '{"type":"exit","code":0}' });
+    ws.close();
+    vi.advanceTimersByTime(5000);
+    expect(MockWebSocket.instances).toHaveLength(1);
+    vi.useRealTimers();
+  });
 });