refactor(plan): remove generic mode abstraction

docs/architecture.zh.md

@@ -37,7 +37,7 @@
 | `ctx.web` | [`web/`](../packages/web/README.md) | 搜索与抓取提供方注册表 |
 | `ctx.compact`，`ctx.toolResultPrune` | [`compact/`](../packages/compact/README.md)/[`compact-tool-result-prune`](../packages/compact/compact-tool-result-prune/README.md) | 摘要压缩（compaction）；可选的无模型结果裁剪 |
 | `ctx.subagents` | [`subagent/`](../packages/subagent/README.md) | 具名委托提供方 |
-| `ctx.modes` | [`mode/`](../packages/mode/README.md) | 落日志的会话模式 |
+| `ctx.planMode` | [`plan/`](../packages/plan/README.md) | 落日志的 plan 协作状态 |
 | `ctx.tasks` | [`tasks/`](../packages/tasks/README.md) | 后台任务注册表和通用 `task_*` 控制工具 |
 | `ctx.workflows` | [`workflow/`](../packages/workflow/README.md) | 脚本驱动的多 agent 编排 |
 | `ctx.goals` | [`goal/`](../packages/goal/README.md) | 持久化的同会话目标 |