🔧 chore(playbook): align repo with latest workflow

sync playbook-managed rules and prompts.
migrate memory-bank to the new structure and move plans to docs/superpowers/plans.
keep product README files untouched.

.agents/cpp/index.md

@@ -43,5 +43,4 @@
 
 ## 与开发规范的关系
 
-- 本仓库内：`docs/standards/playbook/docs/cpp/` 与 `docs/standards/playbook/docs/common/`
-- 目标项目 subtree：`docs/standards/playbook/docs/cpp/` 与 `docs/standards/playbook/docs/common/`
+- 规范文档：`docs/standards/playbook/docs/cpp/` 与 `docs/standards/playbook/docs/common/`