Merge remote-tracking branch 'origin/master' into codex/simp-prune-sandbox-surface

# Conflicts:
#	packages/bash/bash-sandbox/src/index.ts

packages/bash/bash-sandbox/README.md

@@ -10,15 +10,15 @@ Every command is confined by handing the provider the exact `['bash', '-c', comm
 |---|---|
 | `read-only` (default) | No writes anywhere (of `/dev`, only the `/dev/null` node is writable, so `>/dev/null` keeps working) |
 | `workspace-write` | Writes only under `workspaceRoot` + `/tmp` (ephemeral under bwrap, the host `/tmp` under Landlock, `/private/tmp` plus the per-user temp dir under Seatbelt) |
-| `danger-full-access` | No confinement; the provider is never consulted. Execution is `dsh-bash-local`'s verbatim — foreground results still carry `sandbox: { mode, denied: false }` (no `enforcement`: nothing was confined), background tasks carry no sandbox facts |
+| `danger-full-access` | No confinement; the provider is never consulted. Foreground results carry `sandbox: { mode, denied: false }`; background process handles carry no sandbox facts. |
 
 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 `BashRunResult.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).
-- **Runner failures are sandbox failures, never task failures.** A failed run matching the wrap's `runnerFailureSignatures` (the runner's own error prefix — also what the shell prints for a missing runner) means the sandbox itself broke and the command NEVER RAN; the check outranks denial classification because a runner's error text can contain denial words. The foreground path re-throws it as the structured fail-closed `SANDBOX_UNAVAILABLE` error, with the runner's first stderr line as the cause; a settled background task stamps `task.sandbox.runnerFailed` instead (no error channel remains after settle), which `bash_output` renders as its own marker.
-- **Config default, per-call override.** `resolve()` stamps the configured sandbox mode onto each spec unless an approved request supplies a wider mode. That override affects only its call or background task. `ctx.bash.sandboxMode` reports the default so the tool advertises escalation only when supported; results report the effective mode. The model learns standing mode only from tool/result facts, not a system-prompt announcement.
+- **Runner failures are sandbox failures, never command failures.** Foreground execution throws `SANDBOX_UNAVAILABLE`; a settled background process stamps `process.sandbox.runnerFailed`, which the bash producer renders through generic `task_output`. Spawn failures also pass through settlement, so confined background handles retain their mode/enforcement facts and release per-process accounting.
+- **Config-time default, per-call policy.** The DEFAULT mode is fixed by this entry's config for the executor's lifetime; `resolve()` stamps it onto every spec, and an explicit request-level `sandboxMode` override — set by the tool layer only for a call whose wider mode a human granted through `ctx.approval` ([the sandbox RFC § Escalation](../../../docs/rfc/implemented/feature/2026-07-06-sandbox.md)) — makes THAT call run, classify, and report under its own mode while every neighbor keeps the default (background facts are stamped per task at settle). The capability fact `ctx.bash.sandboxMode` reports the configured default so the tool layer advertises escalation only when this executor is mounted. The model learns of the sandbox only through result facts — the static bash tool description explains the denial marker; there is no current-mode statement in the system prompt.
 - **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.
-- Process mechanics (spawn, process-group kills, output collection/spill, background tasks, credential scrub) are inherited verbatim from [`dsh-bash-local`](../bash-local/); the runner ladder, probes, and the per-platform Landlock launcher packages live with [`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.
 
@@ -58,5 +58,5 @@ The keyless consumer-integration proofs are `tests/bwrap.e2e.ts`, `tests/landloc
 
 - **Confinement covers file effects only** — network access and process visibility are unchanged, 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.
-- **A background runner failure has no immediate error channel** — it is recorded on the settled task and surfaces when the caller polls with `bash_output`.
+- **A 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 `task_output`.
 - **`danger-full-access` deliberately bypasses `ctx.sandbox`** — it is an explicit unconfined mode, not a wider sandbox profile.