Complete Sprint 2 (chat hub) and Sprint 3 (color palettes)

Sprint 2 — chat hub:
- Chat tab becomes a list of three conversations: AI assistant
  (featured, gradient card), doctor Syndaev, and clinic administrator
- data.js: new `chats` array with kind, participants, message history,
  online/unread state, time of last message, AI suggestions
- screens-chats.jsx: ChatsListScreen and ChatConversationScreen with
  per-kind UI — AI gets suggestion chips + AI-badge, doctor gets
  video-call button, operator gets phone button
- Recovery surgeon chat button routes to chat:doctor-syndaev directly
- Tab bar auto-hides on pushed chat:<id> routes
- ChatTabScreen removed from screens-misc.jsx

Sprint 3 — color palettes:
- ACCENT_OPTIONS extended with accent/accentDark/accent50,
  p300/success50/fg4 so palette switches change the full theme
  (primary + warm + accent + muted + success)
- New palette "Лагуна" from the design-system screenshot: primary
  #29AEE3 (sky blue), accent #FFA39C (coral), warm #E9E4D4 (beige)
- New palette "Бриз": Лагуна variant with primary #63BAC3 (muted
  teal) and the bright sky blue #29AEE3 demoted to p300
- All 9 screenshot colors wired: #f2fee6→success-50, #93908f→fg-4,
  #63bac3→p300 (visible as border on Clinic Stats card in Home V2)

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/PhoneApp.jsx

@@ -10,9 +10,10 @@ import {
   ApptsTabScreen, ApptDetailScreen,
   ResultsScreen, ResultAudioScreen, ResultEndoscopyScreen,
   RecoveryScreen, AudioTestScreen,
-  ChatTabScreen, ProfileTabScreen, QRScreen,
+  ProfileTabScreen, QRScreen,
   TelemedScreen, MedcardScreen, NotificationsScreen,
 } from './screens/screens-misc.jsx';
+import { ChatsListScreen, ChatConversationScreen } from './screens/screens-chats.jsx';
 import { ArticlesScreen, ArticleDetailScreen } from './screens/screens-articles.jsx';
 import { HomeV2Screen, SearchScreen, ContactsScreen, PricesScreen } from './screens/screens-v2.jsx';
 
@@ -37,7 +38,9 @@ function renderScreen(screenId, nav, ctx) {
     case 'result':          return <ResultEndoscopyScreen nav={nav} resultId={parts[1]} />;
     case 'recovery':        return <RecoveryScreen nav={nav} />;
     case 'audiotest':       return <AudioTestScreen nav={nav} />;
-    case 'chat':            return <ChatTabScreen nav={nav} />;
+    case 'chat':            return parts[1]
+                              ? <ChatConversationScreen nav={nav} chatId={parts[1]} />
+                              : <ChatsListScreen nav={nav} />;
     case 'profile':         return <ProfileTabScreen nav={nav} ctx={ctx} />;
     case 'qr':              return <QRScreen nav={nav} />;
     case 'telemed':         return <TelemedScreen nav={nav} />;
@@ -68,7 +71,8 @@ export function PhoneApp({ initialScreen, ctx }) {
 
   const current = stack[stack.length - 1];
   const rootId = current.split(':')[0];
-  const tabId = rootId === 'home-v2' ? 'home' : (TAB_IDS.includes(rootId) ? rootId : null);
+  const hasSubId = current.includes(':');
+  const tabId = hasSubId ? null : (rootId === 'home-v2' ? 'home' : (TAB_IDS.includes(rootId) ? rootId : null));
   const showTabBar = tabId !== null;
 
   const modalScreens = ['qr', 'telemed', 'booking-success', 'audiotest'];