fix(deepseek): review-driven hardening across the harness integration

Fifteen review findings on the dsh mode, the serious ones first:

- Multi-user: DEEPSEEK_BASE_URL joins the owner-clamped env keys.
  _configureDeepSeek() forwards the SERVER's own DEEPSEEK_API_KEY into
  every dsh pane and applyEnvOverrides() lands after it, so a non-granted
  owner who could redirect the base URL would have the operator's key sent
  as a bearer credential to a host of their choosing.
- Wait registry: until=stop/blocked is refused on docker and remote-SSH
  dsh sessions (new deepSeekBridgeUnreachable fact in sessionHookOptions).
  The HERDR triple is set via LOCAL tmux setenv, which crosses neither
  docker exec nor ssh, so such a session can never post a hook event and
  the wait burned its whole timeout on every turn.
- Approvals: a dsh item is an ALERT, not an answerable card. The answer
  route refuses (the '1'/Esc keystrokes are Claude-dialog-shaped and the
  option parser cannot read a third-party TUI's frames, so an answer was a
  blind keystroke into a foreign composer), and the push notification
  carries no Approve/Deny actions for dsh sessions.
- Status shim (v3): --seq is forwarded and the server drops stale retried
  reports inside a 60s window (the TUI retries with backoff, so a retried
  'working' could land after 'blocked' and resolve an approval whose
  dialog was still on screen); 4xx responses exit 0 instead of retrying,
  so one misconfigured session cannot feed the auth rate-limit bucket
  until the hook endpoint 429s for the whole instance.
- Web-UI server: concurrent starts are serialized through a lock (two
  racing POSTs used to pick the same port and orphan the winner), and the
  readiness poll / timeout paths only clear or stop the singleton while it
  is still theirs. First click actually opens the tab now
  (refreshWebviews, not the nonexistent loadWebviews). DELETE
  /api/deepseek/web requires the privileged grant in multi-user mode.
- Cron: deepseek jobs run the same two-part launch gate as the HTTP
  create paths (impl moved into the resolver so all three share it) and no
  longer stamp a Claude default model on the session.
- Parity sweeps: quick-start's docker branch rejects deepSeekConfig like
  the remote branch; the Ralph auto-enable list gained deepseek;
  HookEventType gained agent_working; the phone overview run menu filters
  managed webview records like the desktop menu.
- install.sh: the dsh identity probe closes stdin (under curl|bash a
  child that reads stdin eats the rest of the script), bounds the exec
  with timeout where available, and is memoized to one scan per install.
- Welcome screen: .welcome-btn-deepseek styled in the #4d6bfe brand
  identity (it rendered as an unstyled UA-grey button); stale markup
  comment about the web shortcut rewritten; clamp docs updated.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

src/web/routes/session-routes.ts

@@ -394,11 +394,12 @@ export const _clampExternalCliBypassForOwner = clampExternalCliBypassForOwner;
 
 /**
  * Env-var keys a non-granted owner must not be able to set, because each one
- * hands back privilege the config clamp above just removed.
+ * hands back privilege the config clamp above just removed — or, for the last,
+ * redirects a credential the server injects.
  *
- * Both are DeepSeek's, and both are reachable because `DSH_*` is an allowlisted
- * `envOverrides` prefix (schemas.ts) — which it has to be, since that is also how
- * a user configures the harness's non-privileged knobs.
+ * All are DeepSeek's, and all are reachable because `DSH_*` and `DEEPSEEK_*` are
+ * allowlisted `envOverrides` prefixes (schemas.ts) — which they have to be, since
+ * that is also how a user configures the harness's non-privileged knobs.
  *
  * - `DSH_PERMISSION_MODE` IS the harness's permission switch. Every other CLI's
  *   bypass is a command-line FLAG, reachable only through the per-CLI config the
@@ -407,8 +408,14 @@ export const _clampExternalCliBypassForOwner = clampExternalCliBypassForOwner;
  * - `DSH_HOME` points the launcher at a profile tree, and a profile's plugin code
  *   executes at BOOT, before any approval row can apply. A user who can write a
  *   workspace can put a profile in it, so this is the wider of the two.
+ * - `DEEPSEEK_BASE_URL` aims the provider endpoint, and `_configureDeepSeek()`
+ *   forwards the SERVER's own `DEEPSEEK_API_KEY` into every dsh pane before
+ *   `applyEnvOverrides()` runs — so a non-granted owner who could set the base
+ *   URL would have the operator's API key sent as a bearer credential to a host
+ *   of their choosing. (`DEEPSEEK_API_KEY` itself stays overridable: supplying
+ *   your OWN key removes privilege rather than granting it.)
  */
-const OWNER_CLAMPED_ENV_KEYS = ['DSH_PERMISSION_MODE', 'DSH_HOME'] as const;
+const OWNER_CLAMPED_ENV_KEYS = ['DSH_PERMISSION_MODE', 'DSH_HOME', 'DEEPSEEK_BASE_URL'] as const;
 
 /**
  * Env-var half of the multi-user bypass clamp.
@@ -456,30 +463,11 @@ export const _clampEnvOverridesForOwner = clampEnvOverridesForOwner;
  * and exits, so both would present as "the tab immediately died".
  */
 async function resolveDeepSeekLaunchError(requestedProfile?: string): Promise<string | null> {
-  const { isDeepSeekAvailable, getDeepSeekNotFoundMessage, listDeepSeekProfiles, resolveDefaultDeepSeekProfile } =
-    await import('../../utils/deepseek-cli-resolver.js');
-  if (!isDeepSeekAvailable()) return getDeepSeekNotFoundMessage();
-
-  const profiles = listDeepSeekProfiles();
-  if (requestedProfile) {
-    const match = profiles.find((p) => p.name === requestedProfile);
-    if (!match) {
-      return `DeepSeek Harness profile "${requestedProfile}" does not exist. Create it with: dsh plugin --profile ${requestedProfile} add <package>`;
-    }
-    if (match.kind === 'web' || match.kind === 'headless') {
-      return `DeepSeek Harness profile "${requestedProfile}" is a ${match.kind} profile and cannot run in a terminal session. Pick an interactive profile, or open the web profile as a Codeman web tab.`;
-    }
-    return null;
-  }
-
-  if (!resolveDefaultDeepSeekProfile()) {
-    return (
-      'No interactive DeepSeek Harness profile is installed. DeepSeek ships only the web and headless ' +
-      'profiles, so the terminal agent comes from a plugin — install one with: ' +
-      'dsh plugin --profile dsh-tui add @deepseek-harness-tui/dsh-tui'
-    );
-  }
-  return null;
+  // Thin async wrapper: the implementation moved into the resolver module so
+  // CRON fires can ask the same question before constructing a Session; the
+  // dynamic import keeps this file's startup free of the probe machinery.
+  const { resolveDeepSeekLaunchError: impl } = await import('../../utils/deepseek-cli-resolver.js');
+  return impl(requestedProfile);
 }
 
 // ═══════════════════════════════════════════════════════════════
@@ -1299,6 +1287,7 @@ export function registerSessionRoutes(
         session.mode !== 'antigravity' &&
         session.mode !== 'pi' &&
         session.mode !== 'grok' &&
+        session.mode !== 'deepseek' &&
         ctx.store.getConfig().ralphEnabled &&
         !session.ralphTracker.autoEnableDisabled
       ) {
@@ -2921,6 +2910,7 @@ export function registerSessionRoutes(
         antigravityConfig ||
         piConfig ||
         grokConfig ||
+        deepSeekConfig ||
         openCodeConfig
       ) {
         return createErrorResponse(