修复 AGC 启动诊断守卫用例

- check-config.mjs 启动诊断守卫改按 StartupLogSlot 契约匹配：setup_log.fail 加稳定失败码
- 同时校验 StartupLogSlot 内部仍写有界诊断日志并调用可见提示，避免守卫被绕过

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

@@ -1705,10 +1705,13 @@ if (
   runtimeConfigSetupStart === -1 ||
   runtimeConfigSetupEnd === -1 ||
   !runtimeConfigSetupSource.includes('sanitize_diagnostic_message(') ||
-  !runtimeConfigSetupSource.includes('append_bounded_diagnostic_line(') ||
+  !runtimeConfigSetupSource.includes('setup_log.fail(') ||
   !runtimeConfigSetupSource.includes(
     'startup.appdata.configure.failed details={details}',
-  )
+  ) ||
+  !tauriHandlerSource.includes('impl StartupLogSlot {') ||
+  !tauriHandlerSource.includes('append_bounded_diagnostic_line(&path, line)') ||
+  !tauriHandlerSource.includes('show_startup_error_dialog(&path)')
 ) {
   throw new Error(
     'AI game creator setup must configure the runtime AppData directory and log sanitized setup failures',