feat(frontend): chat tabs, flat SVG icons, upload autosave, per-user rights

- Chat rework: Chats (private DMs with user search, online dots, unread
  badges) and Team chats tabs; shared message component with reactions,
  edit, image attachments, message search and typing indicators
- Flat modern inline SVG icon set (no external dependency) replaces
  emoji chrome across nav, headers, buttons, tabs and settings
- Uploaded avatar/background images apply instantly (auto-save) with
  confirmation note; per-user permission matrix in dashboard members
- Login localized, invite header uses icon, comment header cleaned

frontend/src/App.vue

@@ -5,9 +5,11 @@ import { useThemeStore } from './stores/theme';
 import { useLocaleStore } from './stores/locale';
 import { useUiStore } from './stores/ui';
 import { fileUrl } from './files';
+import { connectSocket } from './socket';
 import SettingsWindow from './components/SettingsWindow.vue';
 import TimeTrackerButton from './components/TimeTrackerButton.vue';
 import Bell from './components/Bell.vue';
+import Icon from './components/Icon.vue';
 
 const auth = useAuthStore();
 const theme = useThemeStore();
@@ -32,6 +34,7 @@ onMounted(() => {
   locale.set(locale.locale);
   theme.apply();
   auth.applyPrefs();
+  if (auth.isLoggedIn) connectSocket();
 });
 </script>
 
@@ -41,7 +44,7 @@ onMounted(() => {
     <div v-if="auth.isLoggedIn" class="top-right">
       <Bell />
       <TimeTrackerButton />
-      <button class="ghost icon-btn" @click="ui.openSettings()" title="⚙️">⚙️</button>
+      <button class="ghost icon-btn" @click="ui.openSettings()" title="Settings"><Icon name="settings" /></button>
     </div>
     <router-view />
     <SettingsWindow />