refactor(dashboard): reorganize menu actions across sidebar/header/profile

Move shutdown into header popup + profile, move remote into sidebar above
settings, add flag-only language switcher in header, and add language card
plus shutdown/logout actions to the profile page.

Co-authored-by: Cursor <cursoragent@cursor.com>

src/shared/constants/locales.js

@@ -0,0 +1,36 @@
+// Centralized locale display flags (shared across UI components)
+export const LOCALE_FLAGS = {
+  "en": "🇺🇸",
+  "vi": "🇻🇳",
+  "zh-CN": "🇨🇳",
+  "zh-TW": "🇹🇼",
+  "ja": "🇯🇵",
+  "pt-BR": "🇧🇷",
+  "pt-PT": "🇵🇹",
+  "ko": "🇰🇷",
+  "es": "🇪🇸",
+  "de": "🇩🇪",
+  "fr": "🇫🇷",
+  "he": "🇮🇱",
+  "ar": "🇸🇦",
+  "ru": "🇷🇺",
+  "pl": "🇵🇱",
+  "cs": "🇨🇿",
+  "nl": "🇳🇱",
+  "tr": "🇹🇷",
+  "uk": "🇺🇦",
+  "tl": "🇵🇭",
+  "id": "🇮🇩",
+  "th": "🇹🇭",
+  "hi": "🇮🇳",
+  "bn": "🇧🇩",
+  "ur": "🇵🇰",
+  "ro": "🇷🇴",
+  "sv": "🇸🇪",
+  "it": "🇮🇹",
+  "el": "🇬🇷",
+  "hu": "🇭🇺",
+  "fi": "🇫🇮",
+  "da": "🇩🇰",
+  "no": "🇳🇴",
+};