feat: add terminal broadcast, context menu, and shell close

Complete multi-pane broadcast, standard terminal right-click actions, batch host selection with progress, and native ssh_close_shell so closing a pane tears down the remote shell.

Co-authored-by: Cursor <cursoragent@cursor.com>

test/stores/terminalBroadcastStore.test.ts

@@ -0,0 +1,48 @@
+import { beforeEach, describe, expect, it } from 'vitest'
+import {
+  getTerminalBroadcastTargets,
+  terminalBroadcastTargetCount,
+  useTerminalBroadcastStore,
+} from '../../src/stores/terminalBroadcastStore'
+
+describe('terminal broadcast store', () => {
+  beforeEach(() => useTerminalBroadcastStore.getState().reset())
+
+  it('collects ready shells from every open terminal workspace and removes closed tabs', () => {
+    const store = useTerminalBroadcastStore.getState()
+    store.registerWorkspace({
+      tabId: 'tab-a',
+      targets: [
+        { tabId: 'tab-a', paneId: 'left', shellId: 'shell-a', connectionId: 'conn-a', label: 'Host A' },
+        { tabId: 'tab-a', paneId: 'right', shellId: 'shell-b', connectionId: 'conn-a', label: 'Host A' },
+      ],
+    })
+    store.registerWorkspace({
+      tabId: 'tab-b',
+      targets: [
+        { tabId: 'tab-b', paneId: 'main', shellId: 'shell-c', connectionId: 'conn-b', label: 'Host B' },
+      ],
+    })
+
+    expect(getTerminalBroadcastTargets().map((target) => target.shellId)).toEqual([
+      'shell-a',
+      'shell-b',
+      'shell-c',
+    ])
+    expect(terminalBroadcastTargetCount(useTerminalBroadcastStore.getState())).toBe(3)
+
+    useTerminalBroadcastStore.getState().unregisterWorkspace('tab-a')
+    expect(getTerminalBroadcastTargets().map((target) => target.shellId)).toEqual(['shell-c'])
+  })
+
+  it('deduplicates a shell defensively', () => {
+    useTerminalBroadcastStore.getState().registerWorkspace({
+      tabId: 'tab-a',
+      targets: [
+        { tabId: 'tab-a', paneId: 'a', shellId: 'shared', connectionId: 'conn-a', label: 'A' },
+        { tabId: 'tab-a', paneId: 'b', shellId: 'shared', connectionId: 'conn-a', label: 'A' },
+      ],
+    })
+    expect(getTerminalBroadcastTargets()).toHaveLength(1)
+  })
+})