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

server/lib/shell-path.js

@@ -8,7 +8,9 @@
  * timeout bounds a hang. Off with `AGENTHUB_SHELL_PATH=0`. The shell's own
  * PATH is also kept in ITS order (`shellPath()`): the merge appends, so an
  * install job that must use the shell's npm puts this first. Adapted from Orca's
- * `hydrate-shell-path.ts` (MIT).
+ * `hydrate-shell-path.ts` (MIT). `ensureUtf8Locale` fills the other gap such
+ * a service leaves: no locale at all, which makes every `tmux attach` print
+ * `_` for each non-ASCII character.
  * @author Nguyễn Ngọc Trí Vĩ <vinnt@smartgift.vn>
  */
 
@@ -56,4 +58,20 @@ function hydrateShellPath({
   });
 }
 
-module.exports = { hydrateShellPath, shellPath };
+/**
+ * A LaunchAgent (and some service managers) start the dashboard with no
+ * LC_ALL/LC_CTYPE/LANG, and a tmux client whose first set one does not name
+ * UTF-8 replaces every non-ASCII character with `_` — Vietnamese text and
+ * Claude Code's block-art logo in every browser terminal. Default LC_CTYPE
+ * (charset only, no message/date changes) so the attach clients, and the
+ * panes of a tmux server started from here, inherit it. An explicit LC_ALL is
+ * the user's choice and wins; Windows (psmux) is left alone. macOS has no
+ * C.UTF-8, and glibc systems may not have en_US.UTF-8 generated.
+ */
+function ensureUtf8Locale(env = process.env, platform = process.platform) {
+  if (platform === "win32" || env.LC_ALL) return;
+  if (/UTF-?8/i.test(env.LC_CTYPE || env.LANG || "")) return;
+  env.LC_CTYPE = platform === "darwin" ? "en_US.UTF-8" : "C.UTF-8";
+}
+
+module.exports = { hydrateShellPath, shellPath, ensureUtf8Locale };