feat(mobile): add MobileChatScreen with back nav and member list access

packages/web/src/components/layout/MobileChatScreen.tsx

@@ -0,0 +1,86 @@
+import React, { useEffect } from 'react';
+import { useUIStore } from '../../stores/uiStore';
+import { useChatStore } from '../../stores/chatStore';
+import { useSpaceStore } from '../../stores/spaceStore';
+import { useAuthStore } from '../../stores/authStore';
+import { MessageList } from '../chat/MessageList';
+import { MessageInput } from '../chat/MessageInput';
+import { TypingIndicator } from '../chat/TypingIndicator';
+
+interface MobileChatScreenProps {
+  params?: Record<string, string>;
+}
+
+export function MobileChatScreen({ params }: MobileChatScreenProps) {
+  const popMobileScreen = useUIStore((s) => s.popMobileScreen);
+  const pushMobileScreen = useUIStore((s) => s.pushMobileScreen);
+
+  const channelId = params?.channelId;
+  const spaceId = params?.spaceId;
+  const isDm = spaceId === '@me';
+
+  const loadMessages = useChatStore((s) => s.loadMessages);
+  const setCurrentChannel = useChatStore((s) => s.setCurrentChannel);
+  const channels = useSpaceStore((s) => s.channels);
+  const dmChannels = useSpaceStore((s) => s.dmChannels);
+  const authUser = useAuthStore((s) => s.user);
+
+  useEffect(() => {
+    if (!channelId) return;
+    setCurrentChannel(channelId);
+    loadMessages(channelId);
+  }, [channelId, setCurrentChannel, loadMessages]);
+
+  // Resolve channel/DM name
+  let channelName = 'Channel';
+  if (isDm && channelId) {
+    const dm = dmChannels.find(d => d.id === channelId);
+    if (dm) {
+      const otherMembers = dm.members.filter(m => m.id !== authUser?.id);
+      const isGroup = dm.members.length > 2;
+      channelName = isGroup
+        ? otherMembers.map(m => m.displayName ?? m.username).join(', ')
+        : otherMembers[0]?.displayName ?? otherMembers[0]?.username ?? 'Direct Message';
+    }
+  } else if (!isDm && channelId) {
+    const ch = channels.find(c => c.id === channelId);
+    channelName = ch?.name || 'channel';
+  }
+
+  return (
+    <div className="flex flex-col h-full bg-surface-chat">
+      {/* Header */}
+      <header className="h-12 flex items-center gap-2 px-3 border-b border-border-soft bg-surface-base shrink-0">
+        <button onClick={popMobileScreen} className="w-8 h-8 flex items-center justify-center text-txt-secondary hover:text-txt-primary">
+          <svg className="w-5 h-5" fill="none" viewBox="0 0 24 24" stroke="currentColor" strokeWidth={2}>
+            <path strokeLinecap="round" strokeLinejoin="round" d="M15.75 19.5L8.25 12l7.5-7.5" />
+          </svg>
+        </button>
+        <div className="flex-1 min-w-0">
+          <h1 className="text-sm font-semibold text-txt-primary truncate">
+            {isDm ? channelName : `# ${channelName}`}
+          </h1>
+        </div>
+        {!isDm && (
+          <button
+            onClick={() => pushMobileScreen('members')}
+            className="w-8 h-8 flex items-center justify-center text-txt-secondary hover:text-txt-primary"
+          >
+            <svg className="w-5 h-5" fill="none" viewBox="0 0 24 24" stroke="currentColor" strokeWidth={1.5}>
+              <path strokeLinecap="round" strokeLinejoin="round" d="M15 19.128a9.38 9.38 0 002.625.372 9.337 9.337 0 004.121-.952 4.125 4.125 0 00-7.533-2.493M15 19.128v-.003c0-1.113-.285-2.16-.786-3.07M15 19.128v.106A12.318 12.318 0 018.624 21c-2.331 0-4.512-.645-6.374-1.766l-.001-.109a6.375 6.375 0 0111.964-3.07M12 6.375a3.375 3.375 0 11-6.75 0 3.375 3.375 0 016.75 0zm8.25 2.25a2.625 2.625 0 11-5.25 0 2.625 2.625 0 015.25 0z" />
+            </svg>
+          </button>
+        )}
+      </header>
+
+      {/* Messages */}
+      <div className="flex-1 overflow-hidden">
+        <MessageList />
+      </div>
+
+      {/* Typing indicator + Input */}
+      <TypingIndicator />
+      <MessageInput />
+    </div>
+  );
+}

packages/web/src/components/layout/MobileShell.tsx

@@ -17,7 +17,7 @@ import { MobileSpacesScreen } from './MobileSpacesScreen';
 // These will be replaced with real imports as each task is completed:
 const MobileDmsScreen = () => <PlaceholderScreen label="DMs" />;
 const MobileYouScreen = () => <PlaceholderScreen label="You" />;
-const MobileChatScreen = ({ params: _params }: { params?: Record<string, string> }) => <PlaceholderScreen label="Chat" />;
+import { MobileChatScreen } from './MobileChatScreen';
 const MobileSettingsScreen = ({ initialPanel: _p }: { initialPanel?: string }) => <PlaceholderScreen label="Settings" />;
 const MobileVoiceMiniBar = () => null;
 const MobileVoiceFullScreen = () => <PlaceholderScreen label="Voice" />;