feat(switch): 默认扁平化布局，兼容嵌套

- versionSwitchPaths: 新增 FLAT_DIR_NAMES + findFlatPeerEdition()
- resolveRuntimeHome: 检测扁平布局时 home=父目录
- ensureNestedLayout: 扁平优先，无 pendingNest
- prepareEdition: 扁平模式下克隆到同级目录
- EditionLayout 接口 + NestedLayout 别名兼容
- controller: nest skip 消息区分扁平/嵌套
- switch help: 更新布局说明文本

Author: TiaraBasori

src/plugin/switch.ts

@@ -67,7 +67,8 @@ const T = {
       ``,
       `在 TeleBox 和 TeleBox-Next 之间切换。`,
       `session 直接转换，不用重新登录。`,
-      `两版都放在原安装目录下：telebox/telebox-classic 与 telebox/telebox-next。`,
+      `两版默认放在同级目录：telebox 与 telebox-next（或 telebox-classic）。`,
+      `也兼容嵌套布局：telebox/telebox-classic 与 telebox/telebox-next。`,
       ``,
       `两个子命令：`,
       ``,
@@ -271,7 +272,7 @@ const plugin = new (class extends Plugin {
           ``,
           message,
           ``,
-          `会在原运行时目录下使用 telebox-classic / telebox-next 子目录；`,
+          `会在同级目录或原运行时目录下使用 telebox / telebox-next 子目录；`,
           `没有的那一版会自动创建并下载。`,
         ].join("\n"),
       });

src/utils/versionSwitchController.ts

@@ -489,7 +489,7 @@ async function main(): Promise<void> {
     } catch { /* ignore */ }
     await progress.set("stop", "done", "源 bot 已离线，后续由目标版完成通知");
 
-    // Flatten → nested: move live edition into home/telebox-xx after process stopped
+    // Flatten → nested: move live edition into home/telebox-xx after process stopped (nested layout only)
     const nestState = ensureNestedLayout();
     if (nestState.pendingNest) {
       await progress.set("nest", "running");
@@ -510,7 +510,7 @@ async function main(): Promise<void> {
       await progress.set("nest", "done");
     } else {
       REPO_ROOTS = resolveRepoRoots();
-      await progress.set("nest", "skip", "已是嵌套布局");
+      await progress.set("nest", "skip", nestState.flat ? "扁平布局，无需整理" : "已是嵌套布局");
     }
 
     // ── Step 5: Start target (PM2 --cwd = nested edition dir) ─────────