fix: add terminateSession() for explicit close code 4001, keep unmount graceful

Unmount uses a normal close() so the server grace period preserves
session resumability on navigation/reload. A new terminateSession()
method on the AblyCliTerminalHandle ref sends close(4001,
"user-closed-panel") for immediate server cleanup when the user
explicitly closes the panel.

Author: denissellu

packages/react-web-cli/src/AblyCliTerminal.test.tsx

@@ -2557,3 +2557,76 @@ describe("AblyCliTerminal - Initial Command Execution", () => {
     expect(hasTestCmd).toBe(true);
   }, 15_000);
 });
+
+describe("AblyCliTerminal - Unmount cleanup", () => {
+  test("closes socket normally on unmount (no special code for resume support)", async () => {
+    mockClose.mockClear();
+
+    const { unmount } = render(
+      <AblyCliTerminal
+        websocketUrl="wss://test.ably.com"
+        ablyApiKey="test-key"
+      />,
+    );
+
+    await act(async () => {
+      await new Promise((resolve) => setTimeout(resolve, 50));
+    });
+
+    expect(mockSocketInstance).toBeTruthy();
+    expect(mockSocketInstance.readyState).toBe(WebSocket.OPEN);
+
+    unmount();
+
+    // Should close without special code (allows grace period for resume)
+    expect(mockClose).toHaveBeenCalledWith();
+  });
+
+  test("does not call close if socket already closing", async () => {
+    mockClose.mockClear();
+
+    const { unmount } = render(
+      <AblyCliTerminal
+        websocketUrl="wss://test.ably.com"
+        ablyApiKey="test-key"
+      />,
+    );
+
+    await act(async () => {
+      await new Promise((resolve) => setTimeout(resolve, 50));
+    });
+
+    mockSocketInstance.readyState = WebSocket.CLOSING;
+
+    unmount();
+
+    expect(mockClose).not.toHaveBeenCalled();
+  });
+
+  test("terminateSession() sends close code 4001 for immediate cleanup", async () => {
+    mockClose.mockClear();
+    const terminalRef = React.createRef<AblyCliTerminalHandle>();
+
+    render(
+      <AblyCliTerminal
+        ref={terminalRef}
+        websocketUrl="wss://test.ably.com"
+        ablyApiKey="test-key"
+      />,
+    );
+
+    await act(async () => {
+      await new Promise((resolve) => setTimeout(resolve, 50));
+    });
+
+    expect(mockSocketInstance).toBeTruthy();
+    expect(mockSocketInstance.readyState).toBe(WebSocket.OPEN);
+
+    // Call terminateSession explicitly
+    act(() => {
+      terminalRef.current?.terminateSession();
+    });
+
+    expect(mockClose).toHaveBeenCalledWith(4001, "user-closed-panel");
+  });
+});

packages/react-web-cli/src/AblyCliTerminal.tsx

@@ -142,6 +142,8 @@ export interface AblyCliTerminalHandle {
   setSplitPosition: (percent: number) => void;
   /** Read current split state. */
   getSplitState: () => { isSplit: boolean; splitPosition: number };
+  /** Terminate the session immediately. Call this before unmounting when user explicitly closes the panel. */
+  terminateSession: () => void;
 }
 
 // Use shared debug logging
@@ -340,6 +342,23 @@ const AblyCliTerminalInner = (
         setSplitPosition(clamped);
       },
       getSplitState: () => ({ isSplit, splitPosition }),
+      terminateSession: () => {
+        debugLog(
+          "[AblyCLITerminal] terminateSession called - closing with code 4001",
+        );
+        if (
+          socketReference.current &&
+          socketReference.current.readyState < WebSocket.CLOSING
+        ) {
+          socketReference.current.close(4001, "user-closed-panel");
+        }
+        if (
+          secondarySocketReference.current &&
+          secondarySocketReference.current.readyState < WebSocket.CLOSING
+        ) {
+          secondarySocketReference.current.close(4001, "user-closed-panel");
+        }
+      },
     }),
     [
       enableSplitScreen,
@@ -2382,7 +2401,7 @@ const AblyCliTerminalInner = (
         socketReference.current &&
         socketReference.current.readyState < WebSocket.CLOSING
       ) {
-        // close websocket
+        // Normal close (no 4001) so server grace period allows resume
         debugLog("[AblyCLITerminal] Closing WebSocket on unmount.");
         socketReference.current.close();
       }