fix(deepseek): close the env-var clamp hole, bound the profile install, make the hook gate per-session

Three review findings on the DeepSeek Harness mode, plus one the third exposed.

1. The multi-user clamp was bypassable by a sibling field on the same request.
   clampExternalCliBypassForOwner() clamps deepSeekConfig.permissionMode, but
   DSH_* is an allowlisted envOverrides prefix and applyEnvOverrides() runs AFTER
   _configureDeepSeek(), so a non-granted owner sending
   envOverrides.DSH_PERMISSION_MODE landed last and won. Measured on an isolated
   instance: a session created with permissionMode "read-only" and that override
   ran with DSH_PERMISSION_MODE=danger-full-access in its pane.

   Every other CLI's bypass is a command-line flag reachable only through the
   per-CLI config, which is why the config clamp alone is the whole gate for
   them. clampEnvOverridesForOwner() adds the env-var half: for a non-granted
   owner it DROPS DSH_PERMISSION_MODE and DSH_HOME (dropping falls through to
   what _configureDeepSeek() exports, i.e. the clamped value). DSH_HOME is on
   that list because it aims the launcher at a profile tree whose plugin code
   runs at boot, before any approval row can apply. Verified end to end in real
   multi-user mode: a non-granted user sending both now gets workspace-write and
   no DSH_HOME, while an unrelated DSH_TELEMETRY_MODE passes through untouched.

2. POST /api/deepseek/install-profile could hang forever. spawn's own `timeout`
   signals only the direct child, and a plugin install fans out into
   package-manager children that keep the inherited stdio pipes open, so `close`
   never fires and the held-open request leaks with no route-level deadline.
   Reproduced: with a 1.5s built-in timeout the promise was still unsettled after
   6s and both fan-out children were alive. Now detached: true plus negative-pid
   SIGTERM/SIGKILL, the same escalation runGit() uses for the same reason, with a
   last-resort reap for a grandchild that escaped the group. Same probe after the
   change: close fires, direct child and both grandchildren dead.

3. hooksAvailableForMode() promised more than a dsh session can deliver.
   deepSeekConfig.statusReporting: false disarms the HERDR_* export, and that
   triple is the only reason a dsh session posts hook events, so `until=stop` was
   accepted and then blocked for the caller's whole timeout: the exact
   infinite-wait-dressed-as-a-timeout the predicate exists to prevent. It now
   takes HookCapabilityOptions and every call site passes sessionHookOptions(),
   with the deepseek arm reading `!== false` so a forgotten one degrades to the
   old behaviour. The refusal names the setting rather than saying "no Claude
   Code hooks", which would send the caller hunting a bug that is really a
   setting they chose. Profile conformance stays unknowable at request time and
   is documented as such. The stale "True for `claude` and nothing else" docblock
   is corrected.

4. Exposed by (3): hooksAvailableForMode() was doing double duty as "is this a
   claude session". Read My Mind (POST /api/sessions/:id/readmymind) and intent
   capture read Claude's own transcript, and adding deepseek silently widened
   both to a mode that has none. They compare mode === 'claude' directly now, and
   a static check pins them there.

Verified: full CI gate green (6132 passed), typecheck/lint/format clean, and the
wait-signal gating exercised against a live server with a real dsh 0.1.1-rc.2 --
bridge off plus explicit until=stop is a 400 naming the setting, bridge off with
no `until` still 200s on idle/exit, bridge on accepts stop.

src/web/server.ts

@@ -91,7 +91,7 @@ import {
   attachSessionListeners,
   detachSessionListeners,
 } from './session-listener-wiring.js';
-import { sessionWaits, hooksAvailableForMode } from './session-wait-registry.js';
+import { sessionWaits } from './session-wait-registry.js';
 import { intentStore } from '../intent-store.js';
 import { AI_CHECK_MODEL } from '../config/ai-defaults.js';
 import { approvalInbox } from './approval-inbox.js';
@@ -1093,7 +1093,10 @@ export class WebServer extends EventEmitter {
    */
   private async captureIntentPrompt(sessionId: string, text: string): Promise<void> {
     const session = this.sessions.get(sessionId);
-    if (!session || !hooksAvailableForMode(session.mode)) return;
+    // `mode === 'claude'` directly: the intent profile is fed from Claude's own
+    // transcript, so this is a claude question, not a hooks-available one (which
+    // `deepseek` now answers yes to).
+    if (!session || session.mode !== 'claude') return;
     try {
       const settings = await this.readSettings();
       if (settings.readMyMindEnabled !== true) return;