fix: v2.5.9 — Vietnamese in the terminal on macOS, every slash command, the right Claude account

Issue #62: a tmux client whose LC_ALL/LC_CTYPE/LANG names no UTF-8 prints `_`
for every non-ASCII character, and a macOS LaunchAgent starts the dashboard
with no locale at all — Vietnamese text and Claude Code's logo came out as
underscores in every browser terminal.

- shell-path.js: ensureUtf8Locale() defaults LC_CTYPE (en_US.UTF-8 on macOS,
  C.UTF-8 elsewhere) at start, before any tmux call; an explicit LC_ALL and
  Windows are left alone
- RunSetup.tsx: the `/` list now offers Claude Code's bundled skills
  (/code-review, /security-review, /simplify, /loop…) and newer built-ins, and
  every enabled plugin's commands and skills as /<plugin>:<name>
- Claude login decided by the TOKEN's owner (GET /api/oauth/profile, cached
  per token), not by .claude.json: a running session can leave the
  credentials store holding one account's token under another account's
  name. The Profiles modal, its Check quota and the status-bar quota now show
  the account requests are really billed to and warn on the mismatch; a
  switch saves the outgoing token into its OWNER's profile (credentials only)
  instead of overwriting the profile .claude.json names; saving a profile
  while they disagree is refused (EMISMATCH); a saved profile holding another
  account's token reports EWRONGACCOUNT instead of that account's usage
- Running Claude Code sessions follow a switch on their own (they re-read the
  credentials store when it changes), so the "close your sessions first"
  warning is gone

client/src/pages/CcConfig.tsx

@@ -4763,6 +4763,8 @@ function ProfilesModal({
   const { t } = useTranslation("ccConfig");
   const [items, setItems] = useState<CcProfile[] | null>(null);
   const [active, setActive] = useState<CcAccountIdentity | null>(null);
+  /** `.claude.json`'s account, when it is not the one the live token belongs to. */
+  const [mismatchEmail, setMismatchEmail] = useState<string | null>(null);
   const [error, setError] = useState<string | null>(null);
   const [busy, setBusy] = useState<string | null>(null);
   /** `name` of the profile whose label is being edited inline, plus its draft. */
@@ -4787,6 +4789,7 @@ function ProfilesModal({
       const r = await api.ccConfig.profiles();
       setItems(r.items);
       setActive(r.active);
+      setMismatchEmail(r.mismatch ? r.mismatch.configEmail || "?" : null);
       setError(null);
     } catch (err: unknown) {
       setError(err instanceof Error ? err.message : "unknown");
@@ -4931,10 +4934,18 @@ function ProfilesModal({
 
         <div className="px-4 py-3 border-b border-border space-y-2">
           <p className="text-[11px] text-fg-muted leading-relaxed">{t("profiles.subtitle")}</p>
-          <p className="text-[11px] text-status-warning inline-flex items-start gap-1.5 leading-relaxed">
-            <ShieldAlert className="w-3.5 h-3.5 flex-shrink-0 mt-0.5" />
-            <span>{t("profiles.warning")}</span>
-          </p>
+          <p className="text-[11px] text-fg-muted leading-relaxed">{t("profiles.warning")}</p>
+          {mismatchEmail && (
+            <p className="text-[11px] text-status-warning inline-flex items-start gap-1.5 leading-relaxed">
+              <ShieldAlert className="w-3.5 h-3.5 flex-shrink-0 mt-0.5" />
+              <span>
+                {t("profiles.mismatch", {
+                  config: mismatchEmail,
+                  owner: active?.email || active?.accountUuid || "?",
+                })}
+              </span>
+            </p>
+          )}
         </div>
 
         <div className="overflow-auto p-4 space-y-3">

client/src/pages/__tests__/__snapshots__/screens.snapshot.test.tsx.snap

@@ -7233,7 +7233,7 @@ exports[`screen snapshots > Settings — about 1`] = `
             <p
               class="text-[10px] text-status-warning/90 mt-1"
             >
-              UI build v2.5.8 (rebuild client to match)
+              UI build v2.5.9 (rebuild client to match)
             </p>
           </div>
           <div