SpaceRace: Full-width TV field, death line scrolling, camera following leader, jump fix, path never fully blocked, player color on controller

controller/src/screens/JoinScreen.ts

@@ -0,0 +1,50 @@
+import { App } from '../main.js';
+
+export class JoinScreen {
+  private app: App;
+
+  constructor(app: App) {
+    this.app = app;
+    this.init();
+  }
+
+  private init(): void {
+    const joinBtn = document.getElementById('join-btn')!;
+    const roomInput = document.getElementById('room-input') as HTMLInputElement;
+    const nameInput = document.getElementById('name-input') as HTMLInputElement;
+    const errorEl = document.getElementById('join-error')!;
+
+    // Pre-fill room code from URL if present
+    const params = new URLSearchParams(window.location.search);
+    const roomParam = params.get('room');
+    if (roomParam) {
+      roomInput.value = roomParam.toUpperCase();
+    }
+
+    joinBtn.addEventListener('click', () => {
+      const roomCode = roomInput.value.trim().toUpperCase();
+      const playerName = nameInput.value.trim();
+
+      if (!roomCode || roomCode.length !== 4) {
+        errorEl.textContent = 'Enter a 4-character room code';
+        return;
+      }
+      if (!playerName) {
+        errorEl.textContent = 'Enter your name';
+        return;
+      }
+
+      errorEl.textContent = '';
+      joinBtn.textContent = 'Joining...';
+      joinBtn.disabled = true;
+
+      this.app.socket.emit('mobile:joinRoom', { roomCode, playerName }, (res) => {
+        joinBtn.textContent = 'Join Race';
+        joinBtn.disabled = false;
+        if (!res.ok) {
+          errorEl.textContent = res.error || 'Failed to join';
+        }
+      });
+    });
+  }
+}