feat(sidebar): add batch export from project context menu (#81)

- Project context menu gains 'Export sessions…' entry that enters
  batch mode with all project sessions pre-selected.
- Batch toolbar adds 'Export selected (N)' button alongside the
  existing select-all and delete buttons (grid now 3-col).
- handleBatchExport loops over selected sessions, calling the
  existing per-session JSONL export, then exits batch mode.

desktop/src/components/layout/Sidebar.tsx

@@ -1,5 +1,5 @@
 import { useEffect, useState, useCallback, useMemo, useRef } from 'react'
-import { Folder, FolderOpen, MoreHorizontal, Pin, PinOff, RefreshCw, RotateCcw, SquarePen, Trash2, Upload, X } from 'lucide-react'
+import { Download, Folder, FolderOpen, MoreHorizontal, Pin, PinOff, RefreshCw, RotateCcw, SquarePen, Trash2, Upload, X } from 'lucide-react'
 import { useSessionStore } from '../../stores/sessionStore'
 import { useUIStore } from '../../stores/uiStore'
 import { useTranslation } from '../../i18n'
@@ -631,6 +631,19 @@ export function Sidebar({ isMobile = false, onRequestClose }: SidebarProps) {
     setPendingBatchDeleteSessionIds(null)
   }, [exitBatchMode])
 
+  const handleBatchExport = useCallback(async () => {
+    const ids = [...selectedSessionIds]
+    if (ids.length === 0) return
+    let successCount = 0
+    for (const sessionId of ids) {
+      await handleExportSession(sessionId)
+      successCount++
+    }
+    if (successCount > 0) {
+      handleExitBatchMode()
+    }
+  }, [handleExportSession, handleExitBatchMode, selectedSessionIds])
+
   const requestBatchDelete = useCallback((ids: string[]) => {
     if (ids.length === 0) return
     setPendingBatchDeleteSessionIds([...new Set(ids)])
@@ -920,7 +933,7 @@ export function Sidebar({ isMobile = false, onRequestClose }: SidebarProps) {
                     <span className="material-symbols-outlined text-[17px]">close</span>
                   </button>
                 </div>
-                <div className="mt-2 grid grid-cols-2 gap-1.5">
+                <div className="mt-2 grid grid-cols-3 gap-1.5">
                   <button
                     type="button"
                     onClick={() => {
@@ -937,6 +950,14 @@ export function Sidebar({ isMobile = false, onRequestClose }: SidebarProps) {
                       ? t('sidebar.batchDeselectAll')
                       : t('sidebar.batchSelectAll')}
                   </button>
+                  <button
+                    type="button"
+                    onClick={() => void handleBatchExport()}
+                    disabled={selectedCount === 0}
+                    className="rounded-md border border-[var(--color-border)] px-2 py-1.5 text-xs font-medium text-[var(--color-text-secondary)] transition-colors hover:bg-[var(--color-surface-hover)] disabled:opacity-50"
+                  >
+                    {t('sidebar.batchExportSelected', { count: selectedCount })}
+                  </button>
                   <button
                     type="button"
                     onClick={() => requestBatchDelete([...selectedSessionIds])}
@@ -1292,6 +1313,19 @@ export function Sidebar({ isMobile = false, onRequestClose }: SidebarProps) {
             >
               {t('sidebar.importSession')}
             </ProjectMenuItem>
+            <ProjectMenuItem
+              icon={<Download size={18} aria-hidden="true" />}
+              onClick={() => {
+                setProjectContextMenu(null)
+                enterBatchMode()
+                const projectSessionIds = sessions
+                  .filter((s) => (s.workDir || s.projectRoot || s.projectPath) === project.workDir)
+                  .map((s) => s.id)
+                selectSessions(projectSessionIds)
+              }}
+            >
+              {t('sidebar.exportProjectSessions')}
+            </ProjectMenuItem>
             <ProjectMenuItem
               icon={hidden ? <RotateCcw size={18} aria-hidden="true" /> : <X size={18} aria-hidden="true" />}
               onClick={() => toggleHiddenProject(project)}

desktop/src/i18n/locales/en.ts

@@ -92,6 +92,8 @@ export const en = {
   'sidebar.batchDeselectAll': 'Deselect all',
   'sidebar.batchSelectGroup': 'Select {group}',
   'sidebar.batchDeleteSelected': 'Delete selected ({count})',
+  'sidebar.batchExportSelected': 'Export selected ({count})',
+  'sidebar.exportProjectSessions': 'Export sessions…',
   'sidebar.batchDeleteConfirm': 'Delete {count} sessions? This cannot be undone.',
   'sidebar.batchDeleteConfirmBody': 'The following sessions will be deleted:',
   'sidebar.batchDeleteMore': '...and {count} more',

desktop/src/i18n/locales/jp.ts

@@ -94,6 +94,8 @@ export const jp: Record<TranslationKey, string> = {
   'sidebar.batchDeselectAll': 'すべて選択解除',
   'sidebar.batchSelectGroup': '{group} を選択',
   'sidebar.batchDeleteSelected': '選択項目を削除 ({count})',
+  'sidebar.batchExportSelected': '選択項目をエクスポート ({count})',
+  'sidebar.exportProjectSessions': 'セッションをエクスポート…',
   'sidebar.batchDeleteConfirm': '{count} 件のセッションを削除しますか？この操作は取り消せません。',
   'sidebar.batchDeleteConfirmBody': '以下のセッションが削除されます:',
   'sidebar.batchDeleteMore': '...他 {count} 件',

desktop/src/i18n/locales/kr.ts

@@ -94,6 +94,8 @@ export const kr: Record<TranslationKey, string> = {
   'sidebar.batchDeselectAll': '모두 선택 해제',
   'sidebar.batchSelectGroup': '{group} 선택',
   'sidebar.batchDeleteSelected': '선택 항목 삭제 ({count})',
+  'sidebar.batchExportSelected': '선택 항목 내보내기 ({count})',
+  'sidebar.exportProjectSessions': '세션 내보내기…',
   'sidebar.batchDeleteConfirm': '{count}개의 세션을 삭제하시겠습니까? 이 작업은 취소할 수 없습니다.',
   'sidebar.batchDeleteConfirmBody': '다음 세션이 삭제됩니다:',
   'sidebar.batchDeleteMore': '...외 {count}개',

desktop/src/i18n/locales/zh-TW.ts

@@ -94,6 +94,8 @@ export const zh: Record<TranslationKey, string> = {
   'sidebar.batchDeselectAll': '取消全選',
   'sidebar.batchSelectGroup': '選擇{group}',
   'sidebar.batchDeleteSelected': '刪除已選 ({count})',
+  'sidebar.batchExportSelected': '匯出已選 ({count})',
+  'sidebar.exportProjectSessions': '匯出會話…',
   'sidebar.batchDeleteConfirm': '確定要刪除 {count} 個會話嗎？此操作不可撤銷。',
   'sidebar.batchDeleteConfirmBody': '以下會話將被刪除：',
   'sidebar.batchDeleteMore': '...還有 {count} 條',

desktop/src/i18n/locales/zh.ts

@@ -94,6 +94,8 @@ export const zh: Record<TranslationKey, string> = {
   'sidebar.batchDeselectAll': '取消全选',
   'sidebar.batchSelectGroup': '选择{group}',
   'sidebar.batchDeleteSelected': '删除已选 ({count})',
+  'sidebar.batchExportSelected': '导出已选 ({count})',
+  'sidebar.exportProjectSessions': '导出会话…',
   'sidebar.batchDeleteConfirm': '确定要删除 {count} 个会话吗？此操作不可撤销。',
   'sidebar.batchDeleteConfirmBody': '以下会话将被删除：',
   'sidebar.batchDeleteMore': '...还有 {count} 条',