feat(acp): bypassPermissions 默认显示，去掉 opt-in 限制

之前 bypassPermissions 需要本地显式 opt-in（ACP_PERMISSION_MODE 环境变量、
CLAUDE_CODE_ACP_ALLOW_BYPASS_PERMISSIONS 环境变量、或 settings.permissions.defaultMode）
才会出现在 modes 列表里 —— 标准客户端看不到这个 mode，永远没法切换。

去掉 opt-in 后，只要进程级允许（非 root 或 IS_SANDBOX=1）就显示。
- permissionMode: isAcpBypassPermissionModeAvailable 只保留进程级检查，删除
  isAcpBypassLocallyEnabled / isSettingsBypassPermissionMode / isTruthyEnv 等
  只服务于 opt-in 的辅助函数
- createSessionMethod: 调用方去掉 settingsMode 参数
- agent.test: 反转所有依赖 "bypass 需要 opt-in" 的断言

Co-Authored-By: glm-5.2 <zai-org@claude-code-best.win>

src/services/acp/agent/createSessionMethod.ts

@@ -137,10 +137,10 @@ async function createSession(
     // Parse MCP servers from ACP params
     // MCP server config is handled separately in the tools system
 
-    // ACP clients can expose bypass only when both the process and local config allow it.
-    const isBypassAvailable = isAcpBypassPermissionModeAvailable(
-      settingsPermissionMode,
-    )
+    // bypassPermissions is exposed to ACP clients whenever the process itself allows it
+    // (non-root or sandbox). The previous additional opt-in gate made the mode invisible
+    // to standard clients and defeated the purpose of listing it. See permissionMode.ts.
+    const isBypassAvailable = isAcpBypassPermissionModeAvailable()
 
     // Create a mutable AppState for the session
     const appState: AppState = {