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.

scripts/gen-doc-graphs.ts

@@ -188,6 +188,15 @@ const SERVICE_ROLES: ServiceRole[] = [
     consumers: ['tools', 'tool-bash'],
     note: 'One-shot permission decisions dispatched over the `approval/request` waterfall; answerers are listeners (the ACP bridge for its own agents), absence fails closed to `unavailable`.',
   },
+  {
+    key: 'permission',
+    pkg: 'permission',
+    title: 'Permission presets',
+    mode: 'core',
+    implementations: [],
+    consumers: ['acp'],
+    note: 'User-facing preset table (request/yolo) bundling the sandbox-mode and approval-policy knobs; a switch writes one `permission/preset` event through to both knob events.',
+  },
   {
     key: 'codeRuntime',
     pkg: 'code-runtime',