fix(e2b): harden remote startup and teardown

.agents/notes/implemented/feature/2026-07-27-e2b-remote-runtime-poc.i18n.yaml

@@ -2,5 +2,5 @@
 # side as of the last confirmed-consistent state. Both languages carry equal authority;
 # after editing either side, bring the other along and re-record with:
 #   pnpm run verify-translation-pairing --write .agents/notes/implemented/feature/2026-07-27-e2b-remote-runtime-poc.md
-2026-07-27-e2b-remote-runtime-poc.md: 02de8df021094fa326431a996cd183d13b9c0c8c
-2026-07-27-e2b-remote-runtime-poc.zh.md: 3b7ddf761b2cbf950898a0083cf9da653d20e723
+2026-07-27-e2b-remote-runtime-poc.md: cccee91998e832cc9cf53e554e104ccc5caada38
+2026-07-27-e2b-remote-runtime-poc.zh.md: b1a30c92e313b1395006ebd4fd17eacda2546ad5

.agents/notes/implemented/feature/2026-07-27-e2b-remote-runtime-poc.md

@@ -28,7 +28,7 @@ E2B owns the mutable filesystem, managed command and Bash processes, terminal al
 
 The host owns Cordis and plugin objects, the agent loop, agent/session/goal state, session logs and persistence, LLM calls, prompts and tools, authority decisions, skills, subagent orchestration, PTY buffers and readiness state, LSP JSON-RPC ids/queues/protocol state, Code Runtime type stripping/output accounting/binding dispatch, and E2B SDK/network orchestration. The overlay does not upload, mount, or synchronize the host workspace; identical cwd strings name independent host and remote directories.
 
-The fundamental adapters carry the substrate-specific mechanics. `dsh-subprocess-e2b` consumes E2B's byte PTY callback directly, retains terminal send identity across asynchronous foreground-group lookup, and owns whole-session cleanup. For ordinary command pipes, its remote wrapper branches raw spill bytes before framing each live chunk as newline-delimited base64 ASCII; the host restores raw bytes across arbitrary decoded SDK callback boundaries. `dsh-fs-e2b` performs bounded source reads through a dependency-free helper that walks no-follow directory descriptors beneath the canonical target. Generic Code Runtime keeps its controller/worker protocol on validated ASCII/base64 frames and kills the provider-owned process group before inherited pipes drain. Generic LSP uses byte-faithful UTF-8 JSON over command pipes.
+The fundamental adapters carry the substrate-specific mechanics. `dsh-subprocess-e2b` consumes E2B's byte PTY callback directly, retains terminal send identity across asynchronous foreground-group lookup, and owns whole-session cleanup. Ambient environments and ordinary command pipes cross decoded SDK callback boundaries as ASCII/base64 before strict UTF-8 or raw-byte restoration; startup preparation carries the handle's owned cancellation signal, and provisional termination proves the remote group empty after SDK fallback. `dsh-fs-e2b` performs bounded source reads through a dependency-free helper that walks no-follow directory descriptors beneath the canonical target. Generic Code Runtime keeps its controller/worker protocol on validated ASCII/base64 frames and kills the provider-owned process group before inherited pipes drain. Generic LSP uses byte-faithful UTF-8 JSON over command pipes.
 
 Retaining a sandbox preserves remote files and unmanaged remote state only. Reconnect does not reconstruct host PTY sessions, buffers, process handles, LSP connections or requests, code workers, binding calls, timers, output cursors, or locks. Managed groups terminate and join when their provider disposes before the shared owner pauses, leaves, or kills the sandbox.
 

.agents/notes/implemented/feature/2026-07-27-e2b-remote-runtime-poc.zh.md

@@ -28,7 +28,7 @@ E2B 拥有可变文件系统、受管命令与 Bash 进程、终端分配与终
 
 宿主拥有 Cordis 与插件对象、agent loop、agent／会话／goal 状态、会话日志及持久化、LLM（大语言模型）调用、提示词与工具、权限决策、skill（技能）、subagent 编排、PTY 缓冲与就绪状态、LSP JSON-RPC id／队列／协议状态、Code Runtime 类型剥离／输出计量／绑定分发，以及 E2B SDK／网络编排。该 overlay 不会上传、挂载或同步宿主工作区；拼写相同的 cwd 字符串分别指向彼此独立的宿主与远程目录。
 
-基础适配器承载基底专用机制。`dsh-subprocess-e2b` 直接消费 E2B 的字节 PTY 回调，在异步查找前台进程组的过程中保留终端发送身份，并负责全会话清理。对于普通命令管道，其远程包装层会先分流原始 spill 字节，再把每个实时分片编码为换行分隔的 base64 ASCII 帧；宿主会跨任意已解码 SDK 回调边界恢复原始字节。`dsh-fs-e2b` 通过无依赖辅助程序执行有界源码读取，该程序会在规范化目标下逐级遍历不跟随符号链接的目录描述符。通用 Code Runtime 通过经过验证的 ASCII/base64 帧承载 controller/worker 协议，并在继承的管道排空前终止提供方拥有的进程组。通用 LSP 通过命令管道使用字节保真的 UTF-8 JSON。
+基础适配器承载基底专用机制。`dsh-subprocess-e2b` 直接消费 E2B 的字节 PTY 回调，在异步查找前台进程组的过程中保留终端发送身份，并负责全会话清理。环境快照与普通命令管道会先以 ASCII/base64 跨越已解码的 SDK 回调边界，再执行严格 UTF-8 解码或恢复原始字节；启动准备会携带句柄自有的取消信号，临时终止则会在 SDK 回退后证明远程进程组为空。`dsh-fs-e2b` 通过无依赖辅助程序执行有界源码读取，该程序会在规范化目标下逐级遍历不跟随符号链接的目录描述符。通用 Code Runtime 通过经过验证的 ASCII/base64 帧承载 controller/worker 协议，并在继承的管道排空前终止提供方拥有的进程组。通用 LSP 通过命令管道使用字节保真的 UTF-8 JSON。
 
 保留沙箱只会保存远程文件与未受管的远程状态。重新连接不会重建宿主 PTY 会话、缓冲、进程句柄、LSP 连接或请求、代码 worker、绑定调用、定时器、输出游标或锁。受管进程组会在所属提供方 dispose（资源释放）时终止并等待退出，之后共享所有者才会暂停、脱离或终止沙箱。