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/__tests__/cc-profiles.test.js

@@ -384,3 +384,63 @@ describe("cc-profiles", () => {
     assert.throws(() => profiles.listProfiles(), { code: "EBADJSON" });
   });
 });
+
+// The state a running session can leave behind: `.claude.json` still names one
+// account while the credentials store holds ANOTHER account's token. The token
+// is what Claude Code actually uses, so its owner (asked of Anthropic by the
+// route, passed in here) decides who is logged in.
+describe("cc-profiles — identity and token disagree", () => {
+  /** Thắng and Victor saved; then Victor's token lands under Thắng's identity. */
+  function mixedLogin() {
+    login("uuid-t", "t@example.com");
+    profiles.saveProfile("thang");
+    login("uuid-v", "v@example.com");
+    profiles.saveProfile("victor");
+    login("uuid-t", "t@example.com");
+    fs.writeFileSync(
+      CREDS,
+      JSON.stringify({
+        claudeAiOauth: { accessToken: "at-v-new", refreshToken: "rt-v-new", expiresAt: 222 },
+      })
+    );
+    return { uuid: "uuid-v", email: "v@example.com" };
+  }
+  const stored = (name) => profiles.readProfile(name);
+
+  it("marks the token's owner active and reports the disagreement", () => {
+    const owner = mixedLogin();
+    const { items, active, mismatch } = profiles.listProfiles({ owner });
+    assert.deepEqual(
+      items.filter((p) => p.active).map((p) => p.name),
+      ["victor"]
+    );
+    assert.equal(active.email, "v@example.com");
+    assert.equal(mismatch.configEmail, "t@example.com");
+    // Without an owner (offline) the config is all there is, as before.
+    assert.equal(profiles.listProfiles().mismatch, null);
+  });
+
+  it("a switch saves the outgoing token into its OWNER's profile, never the one config names", () => {
+    const owner = mixedLogin();
+    profiles.activateProfile("thang", { owner });
+    assert.equal(stored("victor").credentials.refreshToken, "rt-v-new");
+    assert.equal(stored("victor").account.emailAddress, "v@example.com");
+    assert.equal(stored("thang").credentials.refreshToken, "rt-uuid-t");
+    // And the switch itself landed: Thắng's token and identity, together.
+    assert.equal(JSON.parse(fs.readFileSync(CREDS, "utf8")).claudeAiOauth.accessToken, "at-uuid-t");
+    assert.equal(JSON.parse(fs.readFileSync(CONFIG, "utf8")).oauthAccount.accountUuid, "uuid-t");
+  });
+
+  it("switching to the owner's own profile keeps the live (newest) token and fixes the identity", () => {
+    const owner = mixedLogin();
+    profiles.activateProfile("victor", { owner });
+    assert.equal(JSON.parse(fs.readFileSync(CREDS, "utf8")).claudeAiOauth.refreshToken, "rt-v-new");
+    assert.equal(JSON.parse(fs.readFileSync(CONFIG, "utf8")).oauthAccount.accountUuid, "uuid-v");
+    assert.equal(stored("thang").credentials.refreshToken, "rt-uuid-t");
+  });
+
+  it("refuses to save a profile while they disagree", () => {
+    const owner = mixedLogin();
+    assert.throws(() => profiles.saveProfile(undefined, { owner }), { code: "EMISMATCH" });
+  });
+});