feat: 开放 auto mode 和 bypass mode 给所有用户

通过 Shift+Tab 统一循环：default → acceptEdits → plan → auto → bypassPermissions → default

- 移除 USER_TYPE 分支判断，所有用户使用同一循环路径
- isBypassPermissionsModeAvailable 始终为 true
- isAutoModeAvailable 初始化直接为 true
- 移除 AutoModeOptInDialog 确认流程
- 简化 isAutoModeGateEnabled 仅保留快模式熔断器
- 简化 verifyAutoModeGateAccess 仅检查快模式
- 移除 GrowthBook/Statsig 远程门控
- bypass permissions killswitch 改为 no-op
- 新增 24 个测试覆盖循环逻辑和门控不变量

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/utils/settings/settings.ts

@@ -894,20 +894,8 @@ export function hasSkipDangerousModePermissionPrompt(): boolean {
  * a malicious project could otherwise auto-bypass the dialog (RCE risk).
  */
 export function hasAutoModeOptIn(): boolean {
-  if (feature('TRANSCRIPT_CLASSIFIER')) {
-    const user = getSettingsForSource('userSettings')?.skipAutoPermissionPrompt
-    const local =
-      getSettingsForSource('localSettings')?.skipAutoPermissionPrompt
-    const flag = getSettingsForSource('flagSettings')?.skipAutoPermissionPrompt
-    const policy =
-      getSettingsForSource('policySettings')?.skipAutoPermissionPrompt
-    const result = !!(user || local || flag || policy)
-    logForDebugging(
-      `[auto-mode] hasAutoModeOptIn=${result} skipAutoPermissionPrompt: user=${user} local=${local} flag=${flag} policy=${policy}`,
-    )
-    return result
-  }
-  return false
+  // Auto mode is available to all users — no opt-in needed
+  return true
 }
 
 /**