chore: retire remaining convex infrastructure

- move self-hosted Convex infra and root placeholder into recycle

- update architecture docs to remove active infra/convex deployment guidance

- extend local-first Convex guard to block retired infra regressions

design/00-clean/2026-05-20-cleanup-summary.md

@@ -55,7 +55,7 @@ codegraph status
 
 已更新说明：
 
-- `infra/convex/README.md`
+- `recycle/20260522-convex-runtime-retirement/infra/convex/README.md`
 - `AGENTS.md`
 - `REASONIX.md`
 
@@ -104,7 +104,7 @@ npm ls --depth=0 --json
 - `home/`
 - `.sandbox-home`
 - `.sandbox-tmp`
-- `.convex-tmp`
+- `recycle/20260522-convex-runtime-retirement/local-state/.convex-tmp`
 
 当前该回收目录体积约 `912K`。
 
@@ -230,4 +230,3 @@ find -L node_modules -maxdepth 2 -type l -printf 'BROKEN %p -> %l\n'
 - 不从 `recycle` 中回退引用运行时代码。
 - 新增 CodeGraph 主索引排除项时，应优先判断其是否属于参考代码、生成缓存、测试输出、回收区或本地辅助功能。
 - 后续依赖变化后应重新运行 `pnpm install`，CodeGraph 在代码变化后需要重建或等待 watcher 更新；若排除规则变化，需显式重新初始化 / 重建索引。
-