feat(permission): user-facing permission presets — one Permissions select over the two knobs

A preset names a bundle of the two mechanism knobs — request =
workspace-write + ask, yolo = danger-full-access + never — so the editor
shows ONE 'Permissions' select where the sandbox-mode and approval-policy
tiers stay orthogonal capabilities (the Codex /approvals shape: presets over
two dials). ctx.permission (dsh-permission) owns the config-defined table,
validates the default preset's bundle against the composed knob defaults at
load (fails loud), and writes a switch THROUGH: one log-only
permission/preset event (the audit fact reverse-mapping cannot recover —
the planned 'agent' preset shares request's knob values and differs only in
composed policy) plus each knob event via its own setter, deduped — a
net-zero switch appends nothing. Every knob consumer keeps reading its own
fold, untouched.

The current preset DERIVES from the effective knob values — the fold breaks
bundle ties, a knob state outside the table is the reserved 'custom' value
(a state, not an error: shown while it holds, switchable FROM, never a
target), and defaultPreset disappears (zero-event state reverse-maps from
the composition defaults).

The ACP bridge drops the two per-knob selects for the one preset select
(advertised only when ctx.permission is composed); pending/anchor/no-op
semantics carry over unchanged, with the no-op echo acknowledged before
vocabulary validation so a client re-pushing a derived 'custom' current
never errors. The sandbox variant example composes the
service with a workspace-write default; the permission-switching,
escalation-approved and escalation-rejected scenarios are re-recorded under
it (escalations now target an outside-workspace /tmp path under
danger-full-access, self-cleaning) and config-options is re-authored on the
single-select wire.

docs/rfc/implemented/feature/2026-07-06-sandbox.md

@@ -34,7 +34,7 @@ The swap is invisible to every consumer of `ctx.bash`: the bash tools, hook comm
 
 Misconfiguration fails loud: `mode` outside the closed vocabulary is rejected at plugin load, and a host with no usable backend throws the structured `SANDBOX_UNAVAILABLE` — at `confine()` before the command ever spawns — rather than degrading to unconfined execution. `runnerCommand` on `dsh-sandbox-local` is the operator's explicit assertion of a bwrap-compatible runner (chain and probes skipped); it doubles as the deterministic fake-runner seam for keyless tests.
 
-What the model then experiences: denied file effects come back as result facts with a `[sandbox: file access denied under <mode> mode]` marker plus standing instructions not to retry around them; under a confining executor the schema offers `sandbox_permissions` + `justification` for the one-approval escalated retry (validated strictly wider than the session's effective mode at execution); the system prompt deliberately does NOT state the sandbox mode — the model learns the boundary from the marker (which names the mode) when it hits it, instead of preemptively refusing work a standing declaration discourages. What an ACP editor experiences: a `sandbox-mode` and an `approval-policy` config-option select per session (each advertised only when its knob is composable), switchable at runtime; a sandbox switch simply changes what subsequent commands may do, while an approval-policy switch to `'never'` is stated in the prompt and narrated.
+What the model then experiences: denied file effects come back as result facts with a `[sandbox: file access denied under <mode> mode]` marker plus standing instructions not to retry around them; under a confining executor the schema offers `sandbox_permissions` + `justification` for the one-approval escalated retry (validated strictly wider than the session's effective mode at execution); the system prompt deliberately does NOT state the sandbox mode — the model learns the boundary from the marker (which names the mode) when it hits it, instead of preemptively refusing work a standing declaration discourages. What an ACP editor experiences: one `Permissions` config-option select per session (advertised when the `dsh-permission` preset layer is composed; each preset bundles a sandbox mode and an approval policy and writes through to both knob events — a knob state outside the table derives a switch-away-only `custom` current), switchable at runtime; a sandbox switch simply changes what subsequent commands may do, while an approval-policy switch to `'never'` is stated in the prompt and narrated.
 
 The product path, concretely (the escalation arc is verbatim from the recorded `escalation-approved` scenario; the denial leg is pinned on the real-kernel e2e tier):
 
@@ -57,7 +57,7 @@ Reject instead and nothing executes: the result is the verbatim `the user reject
 - Everything else executes inside the harness process (fs is in-process `node:fs`, web is in-process `fetch`, every `ToolDefinition.execute()` closes over `ctx`): an OS sandbox wraps `execve` and cannot wrap an in-process function call, so "sandbox any tool" is policy at each tool's seam, never a mechanical transport change.
 - `tools/pre-execute` (`allow`/`deny`/`ask`) exists, with `ask` serviced by [the approval seam](2026-07-06-approval-seam.md); the fs intent gates are version guards with no mode input yet.
 - `dsh-bash`'s request/spec split (`BashExecRequest` → `resolve()` → `BashExecSpec`) carries per-call fields the way escalation needs — `owner` is the template: request-optional, spec required-but-nullable, carried verbatim — and the result types already speak `SandboxMode`, so a per-call policy field adds no dependency edge.
-- The pinned-header snapshot design means a schema/description change churns at most one pinning fixture per suite, and the escalation fields are advertised only under a sandboxing executor — so they live in exactly one pinned header, the sandbox example suite's `mode-switching` fixture.
+- The pinned-header snapshot design means a schema/description change churns at most one pinning fixture per suite, and the escalation fields are advertised only under a sandboxing executor — so they live in exactly one pinned header, the acp example suite's `permission-switching` fixture.
 
 #### The seam: `ctx.sandbox`
 
@@ -135,7 +135,7 @@ FIXME: Revisit this tool-local boundary. The follow-up design needs to determine
 - Unit tier (no real runner anywhere): profile dialects, per-platform chain selection (sole candidate unprobed, no chain fails closed, multi-candidate probe order), verdict caching, the fail-closed end, probe-report parsing, and the launcher/`sandbox-exec` CLI contracts via fake runner scripts in `dsh-sandbox-local`; wrapping, policy hand-off, fact stamping, and runner-failure-outranks-denial classification (foreground throw, background `runnerFailed` fact) against a fake provider in `dsh-bash-sandbox`; the error's structured identity in `dsh-sandbox`. The escalation matrix spans the three bash packages: verbatim carry-through in `dsh-bash-local`, stamp/branch/per-task-facts in `dsh-bash-sandbox`, and the capability gate, `justification` pairing, fail-closed texts (pinned verbatim), and grant stamping in `dsh-tool-bash`. The switching surface pins the folds, the stamping precedence, the `'never'` gate, per-session section rendering, the full narrator matrix (cold start, coalescing, net-zero, resume drift with operator wording, positional attribution, persona-shadow hardening), and the bridge's advertisement gating, validation rejections, idle-vs-mid-turn anchoring (dev invariants mounted), and `session/load` reporting over a real two-process JSONL round trip.
 - Keyless real-runner e2e, split along the seam and per rung: CI's `sandbox-e2e` matrix runs bwrap and Landlock on Linux (the Landlock leg once per architecture, each confining through the registry-installed launcher) and Seatbelt on macOS against real kernels, failing on a silent all-skip. World-proofs live in `dsh-sandbox-local` (denied writes absent on disk, workspace writes landing, temp-area grants pinned, kernel denial text matching the advertised dialect) and `dsh-bash-sandbox` (the through-`ctx.bash` consumer proofs, including denied-then-overridden-write-lands). This package's own publish path is rehearsed without publishing (`packed-install.e2e.ts`): `pnpm pack`, tarballs installed into a throwaway consumer with the launcher family resolving from the registry, plain `node` confining through the INSTALLED launcher — asserted executable apart, so a mode-stripped binary can never masquerade as a non-enforcing kernel. The switching surface has its own keyless e2e (the acp-agent example's `escalation.e2e.ts`): the real `sandbox.cordis.yml` tree advertises both options, honors switches end to end, and rejects out-of-vocabulary values.
 - With-key e2e (`examples/acp-agent/tests/escalation.e2e.ts`): real model + real runner + the REAL bridge answerer, world-verified — denied under `read-only`, escalates with justification, the scripted editor grants and the retried write lands on disk, while a rejected escalation leaves no write. Self-skips without `DEEPSEEK_API_KEY` or a usable runner (e2e.yml installs bubblewrap so it actually executes in CI).
-- Snapshot tier (`examples/acp-agent/tests/acp.snapshot.ts`): the keyless config-option wire; the recorded mode-switching arc as the suite's pinned header — necessarily, since mid-session switches emit the `request/header-delta`s the uniformity guard licenses only in the pin — committing both switches, the prompt-section delta and one "changed by the user" notice per knob, and a confined write landing under the switched mode; and both recorded escalation branches over scripted `permissionAnswers` (grant runs confined under `workspace-write`; rejection executes nothing and pins the fail-closed text). Replay re-executes every fixture's bash calls under the host's real runner (ci.yml's snapshot lane installs bubblewrap). Deliberately absent: a fixture carrying a real DENIAL — denial stderr is the backend's dialect and would pin a fixture to its recording platform; the escalation prompts assert the prior denial instead, and the denial→marker path stays on the tiers above.
+- Snapshot tier (`examples/acp-agent/tests/acp.snapshot.ts`): the keyless config-option wire; the recorded permission-switching arc as the pinned header of its class — necessarily, since mid-session switches emit the `request/header-delta`s the uniformity guard licenses only in the pin — committing one `request`→`yolo` preset switch (the `permission/preset` event written through to both knobs), the approval prompt-section delta and its "changed by the user" notice; and both recorded escalation branches over scripted `permissionAnswers` (grant runs under the granted `danger-full-access`; rejection executes nothing and pins the fail-closed text). Replay re-executes every fixture's bash calls under the host's real runner (ci.yml's snapshot lane installs bubblewrap). Deliberately absent: a fixture carrying a real DENIAL — denial stderr is the backend's dialect and would pin a fixture to its recording platform; the escalation prompts assert the prior denial instead, and the denial→marker path stays on the tiers above.
 
 ## Deferred phases