feat(web): permission presets and approval answering for the web UI

The web host now composes the sandboxed product path (sandbox-local +
sandbox-policy behind bash-sandbox/fs-sandbox, with user-approval and
permission on top); BootHostOptions.sandbox carries the deployment
defaults (workspace-write + ask).

createApiProxy owns the approval pending registry: a ctx.approval ask
becomes an answerable approval/requested mux frame with a stable rpcId,
replayed verbatim on every mux open until settled; respond routes by the
echoed rpcId, validates the ApprovalResponsePayload audit correlation,
and broadcasts approval/resolved; the ask's abort signal withdraws the
question as cancelled.

session.permissions / session.setPermission project ctx.permission into
a protocol-owned PermissionOption select; idle switches are held
last-write-wins and
flushed into the next prompted turn (the ACP bridge's anchoring
pattern). The shared hasOpenTurn fold moved to dsh-session,
deduplicating the private copies in user-approval, the ACP bridge, and
the proxy.

Client, per the designer draft: a pending approval takes over the
composer (ApprovalPanel replaces the InputBar — amber strip,
justification headline, paired command, one-shot refuse/allow, keyed by
rpcId so a queued second approval remounts live; the resolved frame
restores the composer); the sidebar session row shows an amber
waiting-approval dot that outranks the running ring (manager-tracked
approvalId set, idempotent under mux-open replays, cleared per
connection generation, lit for uninstantiated sessions too); the
permission selector is a composer bottom-row chip over an invisible
native select, with a presentation-only title-case transform
(workspace-write renders as Workspace Write; wire names untouched). Question placeholders stay in the message flow. The
connection fixture mirrors the host behavior for keyless browser
acceptance.

packages/client/ui-conversation/tests/chat-stats-bash-sample.spec.tsx

@@ -123,8 +123,8 @@ describe('bash sample row', () => {
     return createSnapshotStore<SessionListState>({
       ids: [ROOT, CHILD],
       byId: {
-        [ROOT]: { id: ROOT, title: 'r', displayTitle: 'r', running: false, updatedAt: 0 },
-        [CHILD]: { id: CHILD, title: 'c', displayTitle: 'c', parentId: ROOT, running: false, updatedAt: 0 },
+        [ROOT]: { id: ROOT, title: 'r', displayTitle: 'r', running: false, waitingApproval: false, updatedAt: 0 },
+        [CHILD]: { id: CHILD, title: 'c', displayTitle: 'c', parentId: ROOT, running: false, waitingApproval: false, updatedAt: 0 },
       },
       current: undefined,
     } as SessionListState)
@@ -158,7 +158,7 @@ describe('bash sample row', () => {
     const orphan = 'late-child' as SessionId
     store.update((d) => {
       d.ids.push(orphan)
-      d.byId[orphan] = { id: orphan, title: 'l', displayTitle: 'l', running: false, updatedAt: 0 }
+      d.byId[orphan] = { id: orphan, title: 'l', displayTitle: 'l', running: false, waitingApproval: false, updatedAt: 0 }
     })
     const view = render(<BashRow {...rowProps(orphan, { store })} />)
     expect(view.container.querySelector('[data-sample="bash-global"]')).not.toBeNull()