feat(runtime-host): own plan turn transitions

[M4n5ter]

English

Summary

• add a correlated plan.turn.start command that keeps Plan approval/resume and root Turn startup under one Host-owned Session admission
• reuse one durable identity across Plan mutation and Turn admission, including exact replay after a lost response or Host restart
• reject conflicting Turn descriptors before replaying a Plan mutation
• adapt the Desktop candidate Plan actions to generate and retain retry identities in the renderer, then pass them unchanged through IPC
• advance the compatibility epoch for the expanded operation surface while keeping the experimental wire protocol at v0

Validation

• npm run typecheck
• npm run format:check
• npm run lint
• Runtime Host protocol, real UDS/restart Plan, and Desktop IPC tests (34 passed)
• full Runtime Host suite exercised; the two observed failures both passed isolated reruns after the in-scope contract regression was fixed

Part of #2010.

中文

概要

• 新增关联式 plan.turn.start 命令，使计划批准/恢复与根 Turn 启动统一处于 Host 管理的 Session admission 中
• Plan mutation 与 Turn admission 共用同一个持久身份，可在响应丢失或 Host 重启后进行精确重放
• 在重放 Plan mutation 前拒绝与既有 Turn descriptor 冲突的请求
• Desktop candidate 的 Plan 操作改为由 renderer 生成并保留重试身份，再通过 IPC 原样传递
• 为扩展后的操作面推进 compatibility epoch，同时实验性 wire protocol 继续保持 v0

验证

• npm run typecheck
• npm run format:check
• npm run lint
• Runtime Host 协议、真实 UDS/重启 Plan 和 Desktop IPC 测试（34 项通过）
• 已执行完整 Runtime Host 测试；观察到的两项失败在修复本次范围内的契约回归后，分别精确复跑均通过

属于 #2010 的一部分。