feat(i18n): add multi-language support (ja/ko/vi/ru/zh-TW) with system auto-detection

- Extend AppLanguage to 7 locales: zh-CN, zh-TW, en, ja, ko, vi, ru
- Auto-detect system language via navigator.languages; fallback to English
- Add BCP47 locale mapping for date formatting and sorting
- Create 50 translation JSON files (5 languages × 10 namespaces, 1137 keys each)
- Update language selector with native language names
- Extend locale key parity test to cover all 7 languages (70 assertions)
- Add VNC/RDP desktop, serial terminal, AI agent, port forwarding, and SFTP features
- Add credential encryption, host metrics, session backup crypto, and zmodem bridge
- Update Rust backend: desktop services, host metrics, SSH/SFTP enhancements

test/stores/terminalBroadcastStore.test.ts

@@ -1,6 +1,7 @@
 import { beforeEach, describe, expect, it } from 'vitest'
 import {
   getTerminalBroadcastTargets,
+  selectBroadcastTargetCount,
   terminalBroadcastTargetCount,
   useTerminalBroadcastStore,
 } from '../../src/stores/terminalBroadcastStore'
@@ -8,7 +9,40 @@ import {
 describe('terminal broadcast store', () => {
   beforeEach(() => useTerminalBroadcastStore.getState().reset())
 
-  it('collects ready shells from every open terminal workspace and removes closed tabs', () => {
+  it('defaults scope to current-tab', () => {
+    expect(useTerminalBroadcastStore.getState().scope).toBe('current-tab')
+  })
+
+  it('collects ready shells from every open terminal workspace when scope is all', () => {
+    const store = useTerminalBroadcastStore.getState()
+    store.setScope('all')
+    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: 'local', label: 'Local' },
+      ],
+    })
+
+    expect(getTerminalBroadcastTargets().map((target) => target.shellId)).toEqual([
+      'shell-a',
+      'shell-b',
+      'shell-c',
+    ])
+    expect(terminalBroadcastTargetCount(useTerminalBroadcastStore.getState())).toBe(3)
+    expect(selectBroadcastTargetCount('tab-a')(useTerminalBroadcastStore.getState())).toBe(3)
+
+    useTerminalBroadcastStore.getState().unregisterWorkspace('tab-a')
+    expect(getTerminalBroadcastTargets().map((target) => target.shellId)).toEqual(['shell-c'])
+  })
+
+  it('limits targets to the source tab when scope is current-tab', () => {
     const store = useTerminalBroadcastStore.getState()
     store.registerWorkspace({
       tabId: 'tab-a',
@@ -24,15 +58,13 @@ describe('terminal broadcast store', () => {
       ],
     })
 
-    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'])
+    expect(getTerminalBroadcastTargets('tab-a').map((t) => t.shellId)).toEqual(['shell-a', 'shell-b'])
+    expect(getTerminalBroadcastTargets('tab-b').map((t) => t.shellId)).toEqual(['shell-c'])
+    const latest = useTerminalBroadcastStore.getState()
+    expect(selectBroadcastTargetCount('tab-a')(latest)).toBe(2)
+    expect(selectBroadcastTargetCount('tab-b')(latest)).toBe(1)
+    // Without source tab id, current-tab must not silently expand to all tabs
+    expect(getTerminalBroadcastTargets()).toEqual([])
   })
 
   it('deduplicates a shell defensively', () => {
@@ -43,6 +75,6 @@ describe('terminal broadcast store', () => {
         { tabId: 'tab-a', paneId: 'b', shellId: 'shared', connectionId: 'conn-a', label: 'A' },
       ],
     })
-    expect(getTerminalBroadcastTargets()).toHaveLength(1)
+    expect(getTerminalBroadcastTargets('tab-a')).toHaveLength(1)
   })
 })