收紧移动壳文本导出校验顺序

移动壳文本导出先校验 MIME 再探测原生分享能力

移动壳文件测试覆盖非法文本 MIME 不触碰原生分享

移动壳配置检查锁定文本导出本地校验顺序

apps/mobile-shell/scripts/check-config.mjs

@@ -2104,6 +2104,20 @@ if (
 ) {
   throw new Error('mobile shell image export must reject empty and oversized bytes');
 }
+const exportTextFileBody = extractFunctionBody(filesSource, 'exportTextFile');
+const exportTextMimeValidationIndex = exportTextFileBody.indexOf(
+  'HOST_BRIDGE_TEXT_MIME_TYPE_SET.has(mimeType as HostBridgeTextMimeType)',
+);
+const exportTextSharingAvailabilityIndex = exportTextFileBody.indexOf(
+  'await assertMobileFileSharingAvailable()',
+);
+if (
+  exportTextMimeValidationIndex < 0 ||
+  exportTextSharingAvailabilityIndex < 0 ||
+  exportTextMimeValidationIndex > exportTextSharingAvailabilityIndex
+) {
+  throw new Error('mobile shell text export must validate MIME before native sharing checks');
+}
 
 for (const [wrapperName, fileCall] of [
   ['exportMobileHostBridgeTextFile', 'ok(request, await exportTextFile(request.payload))'],
@@ -2126,6 +2140,7 @@ for (const snippet of [
   'exportTextFile({',
   'exportImageFile({',
   'rejects every export before cache writes when system sharing is unavailable',
+  'rejects invalid text export MIME before touching native sharing',
   'const exportCases = [',
   'expect(writtenFiles).toHaveLength(0)',
   'importTextFile()',