Resilient prepare, Twitch chat echo, parallel chat startup

- Prepare endpoint wraps each destination in try/catch; partial success
  if at least one destination is ready (e.g., Twitch works when YouTube
  is rate-limited)
- Echo sent Twitch messages back to app WebSocket (IRC doesn't echo
  your own PRIVMSGs)
- Start YouTube and Twitch chat clients in parallel via Promise.allSettled
- Fix Twitch auth failure detection (Login unsuccessful + Login
  authentication failed)
- Add Twitch IRC debug logging

src/services/twitch-chat.service.ts

@@ -33,6 +33,7 @@ export class TwitchChatClient extends EventEmitter {
     this.ws = new WebSocket('wss://irc-ws.chat.twitch.tv:443');
 
     this.ws.on('open', () => {
+      console.log(`[Twitch-IRC] WebSocket open for #${this.channel}`);
       if (!this.ws) return;
       // Request capabilities
       this.ws.send('CAP REQ :twitch.tv/tags twitch.tv/commands');
@@ -45,19 +46,22 @@ export class TwitchChatClient extends EventEmitter {
 
     this.ws.on('message', (data: Buffer) => {
       const raw = data.toString();
+      console.log(`[Twitch-IRC] #${this.channel} << ${raw.trim().substring(0, 200)}`);
       const lines = raw.split('\r\n').filter(Boolean);
       for (const line of lines) {
         this.handleLine(line);
       }
     });
 
-    this.ws.on('close', () => {
+    this.ws.on('close', (code: number, reason: Buffer) => {
+      console.log(`[Twitch-IRC] #${this.channel} closed: ${code} ${reason.toString()}`);
       this.connected = false;
       this.cleanup();
       this.emit('disconnected');
     });
 
     this.ws.on('error', (err: Error) => {
+      console.log(`[Twitch-IRC] #${this.channel} error: ${err.message}`);
       this.emit('error', err);
     });
 
@@ -106,8 +110,8 @@ export class TwitchChatClient extends EventEmitter {
     }
 
     // Handle auth failure
-    if (line.includes('NOTICE') && line.includes('Login authentication failed')) {
-      this.emit('error', new Error('missing_scopes'));
+    if (line.includes('NOTICE') && (line.includes('Login unsuccessful') || line.includes('Login authentication failed'))) {
+      this.emit('error', new Error('Twitch login failed — token may be expired or missing chat scopes'));
       this.disconnect();
       return;
     }