补齐AGC跨平台路径确定性回归

新增链接父目录与不存在叶目录的跨平台测试
将临时路径规范化纳入可靠清理边界
同步跨平台路径回归文档与踩坑记录

apps/ai-game-creator-shell/scripts/check-config.mjs

@@ -435,8 +435,29 @@ async function runConfigWizardRegressionChecks() {
   const testRoot = fs.mkdtempSync(
     path.join(os.tmpdir(), 'genarrative-agc-config-check-'),
   );
-  const canonicalTestRoot = fs.realpathSync.native(testRoot);
   try {
+    const canonicalTestRoot = fs.realpathSync.native(testRoot);
+    const realConfigAncestor = path.join(testRoot, 'real-config-ancestor');
+    const linkedConfigAncestor = path.join(testRoot, 'linked-config-ancestor');
+    fs.mkdirSync(realConfigAncestor);
+    fs.symlinkSync(
+      realConfigAncestor,
+      linkedConfigAncestor,
+      process.platform === 'win32' ? 'junction' : 'dir',
+    );
+    const missingLinkedConfigDir = path.join(
+      linkedConfigAncestor,
+      'missing-appdata',
+    );
+    assert.equal(fs.existsSync(missingLinkedConfigDir), false);
+    assert.equal(
+      await assertSafeGameCreatorConfigDestination(missingLinkedConfigDir),
+      path.join(
+        fs.realpathSync.native(realConfigAncestor),
+        'missing-appdata',
+      ),
+    );
+
     const gitRoot = path.join(testRoot, 'tracked-repository');
     const trackedConfigDir = path.join(gitRoot, 'runtime-config');
     fs.mkdirSync(trackedConfigDir, { recursive: true });