fix: add unmount cleanup for timer-leaking scenes (#63, #91, #204-206)

- tournament-arena, tournament-lobby, tournament-live: export unmount
- group-chat: export unmount to clear realtime sub + invite timer
- social/mod.js: register unmountChat and unmountGroupChat
- Prevents interval leaks when navigating away from these scenes
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

public/js/modules/rank/scenes/tournament-arena.js

@@ -158,3 +158,5 @@ function cleanup() {
   if (pollInterval) { clearInterval(pollInterval); pollInterval = null; }
   if (countdownInterval) { clearInterval(countdownInterval); countdownInterval = null; }
 }
+
+export const unmountTournamentArena = cleanup;

public/js/modules/rank/scenes/tournament-live.js

@@ -133,3 +133,7 @@ async function loadLiveData(el, tournamentId) {
     content.innerHTML = '<div style="text-align:center;color:var(--error);">فشل التحميل</div>';
   }
 }
+
+export function unmountTournamentLive() {
+  if (refreshInterval) { clearInterval(refreshInterval); refreshInterval = null; }
+}

public/js/modules/rank/scenes/tournament-lobby.js

@@ -116,3 +116,5 @@ function cleanup() {
   if (countdownInterval) { clearInterval(countdownInterval); countdownInterval = null; }
   if (unsub) { unsub(); unsub = null; }
 }
+
+export const unmountTournamentLobby = cleanup;

public/js/modules/social/mod.js

@@ -2,17 +2,17 @@ import * as scene from '../../core/scene.js';
 import { mountFriends, unmountFriends } from './scenes/friends.js';
 import { mountNotifications } from './scenes/notifications.js';
 import { mountActivity } from './scenes/activity.js';
-import { mountChat } from './scenes/chat.js';
+import { mountChat, unmountChat } from './scenes/chat.js';
 import { mountGroups } from './scenes/groups.js';
 import { mountGroupCreate } from './scenes/group-create.js';
-import { mountGroupChat } from './scenes/group-chat.js';
+import { mountGroupChat, unmountGroupChat } from './scenes/group-chat.js';
 import { mountGroupMembers } from './scenes/group-members.js';
 
 scene.register('friends', mountFriends, unmountFriends);
 scene.register('notifications', mountNotifications);
 scene.register('activity-feed', mountActivity);
-scene.register('friend-chat', mountChat);
+scene.register('friend-chat', mountChat, unmountChat);
 scene.register('groups', mountGroups);
 scene.register('group-create', mountGroupCreate);
-scene.register('group-chat', mountGroupChat);
+scene.register('group-chat', mountGroupChat, unmountGroupChat);
 scene.register('group-members', mountGroupMembers);

public/js/modules/social/scenes/group-chat.js

@@ -297,6 +297,8 @@ function cleanup() {
   if (inviteTimer) { clearInterval(inviteTimer); inviteTimer = null; }
 }
 
+export const unmountGroupChat = cleanup;
+
 function escapeHtml(str) {
   const div = document.createElement('div');
   div.textContent = str;