fix: 完善聊天解析与导出体验

- 修复引用消息名称和图片布局
- 明确单会话图片测试日志范围
- 支持导出文件附件
- 完善图片批测、会话刷新和安全退出

tests/unit/file-asset-service.test.ts

@@ -0,0 +1,30 @@
+import { mkdirSync, mkdtempSync, realpathSync, rmSync, writeFileSync } from 'fs'
+import { join } from 'path'
+import { tmpdir } from 'os'
+import { afterEach, describe, expect, it } from 'vitest'
+import { FileAssetService } from '../../src/main/file-asset-service'
+
+const roots: string[] = []
+
+afterEach(() => {
+  for (const root of roots.splice(0)) rmSync(root, { recursive: true, force: true })
+})
+
+describe('file asset service', () => {
+  it('prefers the message month and supports duplicate download suffixes', () => {
+    const accountRoot = mkdtempSync(join(tmpdir(), 'wxe-file-asset-'))
+    roots.push(accountRoot)
+    const august = join(accountRoot, 'msg', 'file', '2026-08')
+    const july = join(accountRoot, 'msg', 'file', '2026-07')
+    mkdirSync(august, { recursive: true })
+    mkdirSync(july, { recursive: true })
+    writeFileSync(join(july, '产品说明.txt'), 'old')
+    writeFileSync(join(august, '产品说明(1).txt'), 'current')
+
+    const service = new FileAssetService({ getAccountRoot: () => accountRoot })
+    const result = service.resolve('产品说明.txt', new Date(2026, 7, 4).getTime() / 1000)
+
+    expect(result).toMatchObject({ success: true, fileName: '产品说明(1).txt' })
+    expect(result.filePath).toBe(realpathSync(join(august, '产品说明(1).txt')))
+  })
+})