fix(sandbox): isolate bwrap PID namespace

packages/shell/bash-sandbox/README.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 packages/shell/bash-sandbox/README.md
-README.md: fe9a0b1a891bd2b9102357f48141822c70465ddf
-README.zh.md: 648264615dc476f9442b9bb9ae3a332196f4e104
+README.md: dd0f6dd80394ee8bf0349f706e8fd77cd3c14189
+README.zh.md: 6670058e3b8d14f72bf0133d40a433b82b17e4fa

packages/shell/bash-sandbox/README.md

@@ -19,7 +19,7 @@ Semantics:
 - **Denials are result facts.** A failed run whose stderr carries the selected backend's own denial dialect — the signatures the provider stamps on every wrap (EROFS text under bwrap, EACCES under Landlock, EPERM under Seatbelt) — is reported as `ShellRunResult.sandbox.denied: true` (conservative classification, read from the collected stderr tail); every CONFINED run also carries the mode it executed under (`result.sandbox.mode`) and the provider's enforcement completeness (`result.sandbox.enforcement`: `full`, or `partial` on an older Landlock ABI).
 - **The runner path or syscall must match.** Before a process starts, a rejection is attributed to the runner only when the caller-owned workdir is independently usable and Node reports `ENOENT` or `EACCES` with either an `error.path` equal to provider argv[0] or, when `error.path` is absent, an exact `syscall: 'spawn <runner>'`. A present path also requires `syscall: 'spawn'` or the exact `spawn <runner>`. This covers a missing runner, a non-executable runner, or an executable script whose shebang interpreter is unavailable. A bare `syscall: 'spawn'` without an exact error path, any other code, an invalid or unusable workdir, a resource failure, an unrelated syscall, or an unstructured rejection retains the local executor's command-start failure semantics. Foreground execution throws `SANDBOX_UNAVAILABLE` with the original spawn detail, while asynchronous background settlement stamps `runnerFailed: true` and `denied: false`. If a `SubprocessRuntime` synchronously throws the same runner-identifying `ENOENT`/`EACCES` shape, background start throws `SANDBOX_UNAVAILABLE`; other synchronous errors propagate unchanged. After a process starts, a rule's optional exit-code check and a remaining fatal stderr line must both match after exact informational-line exclusions. A match takes priority over denial; foreground execution throws `SANDBOX_UNAVAILABLE` with the matched fatal line, while a settled background process stamps `process.sandbox.runnerFailed`, which the bash producer renders through generic `job_output`. Confined background handles retain their mode/enforcement facts and release per-process accounting in either path.
 - **Deployment fallback, per-call policy.** [`ctx.sandboxPolicy`](../../sandbox/sandbox-policy/) resolves a complete `SandboxExecutionPolicy` for every tool call: the calling session supplies its mode override and immutable cwd root, while deployment config supplies the fallbacks for agentless calls. An approved escalation changes only that policy's mode; its session root stays attached. `resolve()` carries the policy onto the spec, so overlapping commands from different projects run, classify, and report under their own roots and modes. The capability fact `ctx.shell.sandboxMode` reports the configured default so the tool layer advertises escalation only when this executor is mounted; the static bash tool description separately owns denial and escalation guidance.
-- **File effects only.** Network and process visibility are deliberately not restricted — the mode vocabulary does not pretend to cover what the backend does not enforce.
+- **File effects only.** The mode vocabulary claims only file effects. Network stays unrestricted; process visibility is backend-specific and documented by [`dsh-sandbox-local`](../../sandbox/sandbox-local/).
 - Process mechanics (spawn, process-group kills, output collection/spill, background handles, credential scrub) are inherited from [`dsh-bash-local`](../bash-local/); runner selection lives in [`dsh-sandbox-local`](../../sandbox/sandbox-local/).
 
 Deny-only at the seam: a denial is a reported fact, and this executor never negotiates permissions itself — the approval question lives in the tool layer (`dsh-tool-bash`), which drives the override this package honors.
@@ -82,7 +82,7 @@ Append-only; newly visible content follows the reusable request prefix and does
 
 ## Known Limitations and Deferred Work
 
-- **Confinement covers file effects only** — network access and process visibility are unchanged, so the modes are not a general-purpose security sandbox.
+- **Confinement covers file effects only** — network restriction and a uniform process-visibility guarantee are absent, so the modes are not a general-purpose security sandbox.
 - **Denials are inferred from failed-command stderr** — backend signatures make the inference portable, but a matching application error can be classified as a denial and a denial omitted from the retained tail can be missed.
 - **An asynchronously observed background runner failure has no immediate error channel** — it is recorded on the settled process and surfaces when the caller reads the generic task with `job_output`; a synchronous `SubprocessRuntime` throw that names the runner path instead fails `start()` immediately.
 - **`danger-full-access` deliberately bypasses `ctx.sandbox`** — it is an explicit unconfined mode, not a wider sandbox profile.

packages/shell/bash-sandbox/README.zh.md

@@ -19,7 +19,7 @@
 - **拒绝是结果事实。** 如果一次失败运行的 stderr 包含所选后端自身的拒绝方言，即提供方在每次包装时加上的特征（bwrap 下的 EROFS 文本、Landlock 下的 EACCES、Seatbelt 下的 EPERM），则结果报告 `ShellRunResult.sandbox.denied: true`（从已收集的 stderr 尾部进行保守分类）。每次受限制运行还会携带执行时模式（`result.sandbox.mode`）与提供方强制执行完整性（`result.sandbox.enforcement`：`full`，或在较旧 Landlock ABI 上为 `partial`）。
 - **Runner 路径或 syscall 必须匹配。** 进程启动前，调用方拥有的 workdir 必须经独立验证可用，Node 必须报告 `ENOENT` 或 `EACCES`，并且错误必须符合以下一种形态：`error.path` 等于提供方返回的 `argv[0]`，同时 `syscall` 为 `'spawn'` 或精确的 `'spawn <runner>'`；或者 `error.path` 不存在，同时 `syscall` 为精确的 `'spawn <runner>'`。这样可以识别缺失的 runner、不可执行的 runner，或 shebang 解释器不可用的可执行脚本。没有精确错误路径的裸 `syscall: 'spawn'`、任何其他错误码、无效或不可用的 workdir、资源失败、无关 syscall 或无结构拒绝仍保留本地执行器的命令启动失败语义。前台执行会抛出 `SANDBOX_UNAVAILABLE` 并附带原始 spawn 错误详情，异步后台结算则会标记 `runnerFailed: true` 和 `denied: false`。如果 `SubprocessRuntime` 同步抛出同样能指明 runner 的 `ENOENT`／`EACCES` 形态，后台启动会抛出 `SANDBOX_UNAVAILABLE`；其他同步错误原样传播。进程启动后，先按整行精确匹配排除信息性行，随后规则的可选退出码检查和余下 stderr 中的一行致命诊断必须同时匹配。匹配结果优先于拒绝；前台执行会抛出 `SANDBOX_UNAVAILABLE` 并附带匹配到的致命行，已结算的后台进程则会标记 `process.sandbox.runnerFailed`，Bash 结果生成方通过通用 `job_output` 渲染它。无论走哪条路径，受限制的后台句柄都会保留自身的模式／强制执行事实，并释放每进程计数。
 - **部署回退，每次调用策略。** [`ctx.sandboxPolicy`](../../sandbox/sandbox-policy/) 为每次工具调用解析完整的 `SandboxExecutionPolicy`：调用会话提供自身的模式覆盖与不可变 cwd 根目录，部署配置则为无 agent（智能体）调用提供回退。已批准的升权只更改该策略的模式，会话根目录仍然附着其上。`resolve()` 把策略带入 spec，因此来自不同项目的重叠命令会在各自的根目录与模式下运行、分类和报告。能力事实 `ctx.shell.sandboxMode` 报告已配置的默认值，因此工具层只在装载该执行器时才公布升权；静态 bash 工具描述则单独负责拒绝与升权引导。
-- **只限制文件影响。** 设计上不限制网络与进程可见性：模式词汇不会声称覆盖后端未强制执行的范围。
+- **只限制文件影响。** 模式词汇只声称文件影响。网络仍不受限制；进程可见性因后端而异，具体见 [`dsh-sandbox-local`](../../sandbox/sandbox-local/)。
 - 进程机制（spawn、进程组终止、输出收集／spill、后台句柄、凭证清理）继承自 [`dsh-bash-local`](../bash-local/)；runner 选择位于 [`dsh-sandbox-local`](../../sandbox/sandbox-local/)。
 
 该 seam 只报告拒绝：拒绝是一项结果事实，本执行器绝不自行协商权限。批准问题位于工具层（`dsh-tool-bash`），由它设置本包所遵守的模式覆盖值。
@@ -82,7 +82,7 @@
 
 ## 已知限制与暂缓事项
 
-- **限制只覆盖文件影响**：网络访问与进程可见性不变，因此这些模式不是通用安全沙箱。
+- **限制只覆盖文件影响**：不提供网络限制和统一的进程可见性保证，因此这些模式不是通用安全沙箱。
 - **拒绝从失败命令的 stderr 推断**：后端特征使该推断可跨平台使用，但包含相同后端特征的应用错误可能被分类为拒绝，也可能遗漏未出现在保留尾部中的拒绝。
 - **异步观测到的后台 runner 失败没有即时错误通道**：它记录在已结算进程上，并在调用方使用 `job_output` 读取通用任务时呈现；`SubprocessRuntime` 同步抛出的错误包含 runner 路径时，则会使 `start()` 立即失败。
 - **`danger-full-access` 有意绕过 `ctx.sandbox`**：它是显式无约束模式，不是更宽的沙箱 profile。