chore(phase1): surface audit and cleanup

- Remove _bmad/ and _bmad-output/ gitignore entries (tasks 1.1, 1.2):
  directories were never tracked by git; entries are no longer needed
- changelog/ was already absent from git (empty dir, not tracked) (task 1.3)
- Create docs/TRANSLATION_SCOPE.md declaring bilingual scope policy (task 1.4)
- Add zh/index.md note directing Chinese readers to English exercises (task 1.4)
- VitePress build confirmed: dist/index.html present, no errors (task 1.5)
- Node.js v22.22.0 matches pages.yml node-version: 22; VitePress ^1.6.3 is stable (task 1.6)

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: LessUp

.gitignore

@@ -210,9 +210,5 @@ build_errors.txt
 .vscode/settings.json.user
 .vscode/launch.json.user
 
-# BMad Method V6
-_bmad/
-_bmad-output/
-
 # Local git worktrees
 .worktrees/

docs/TRANSLATION_SCOPE.md

@@ -0,0 +1,35 @@
+# Translation Scope Policy
+
+This document defines which documentation surfaces are maintained bilingually
+(English + Simplified Chinese) and which are English-only by design.
+
+## Bilingual surfaces
+
+The following directories are fully bilingual. Every page in `docs/en/` has a
+corresponding page in `docs/zh/`:
+
+- `getting-started/`
+- `guides/`
+- `reference/` (top-level pages: `faq.md`, `troubleshooting.md`, `api-reference.md`)
+- `contributing/`
+
+## English-only surfaces
+
+The following are maintained in English only. Chinese readers are directed to the
+English version:
+
+- `exercises/` — lab exercises and solutions are tightly coupled to code
+  examples; translating them would increase maintenance cost without proportional
+  reader benefit.
+- `reference/api/` — auto-generated or low-level API detail pages.
+
+## Reader guidance
+
+A note is present in `docs/zh/index.md` directing Chinese readers to the English
+exercises section when they reach that part of the learning path.
+
+## Maintenance rule
+
+When adding a new page to a bilingual surface, add it to both `docs/en/` and
+`docs/zh/` in the same commit. When adding a page to an English-only surface,
+no Chinese counterpart is required.

docs/zh/index.md

@@ -17,6 +17,11 @@
 - **参考文档** —— FAQ、故障排查、API 入口
 - **贡献流程** —— AI 辅助与 OpenSpec 驱动的开发模式
 
+## 练习与实验室
+
+练习模块（`exercises/`）和 API 参考子页面仅提供英文版本，请直接访问
+[英文练习页面](/en/exercises/README)。
+
 ## 贡献者提示
 
 如果你要修改仓库本身，请同时参考：