Let viewers set a per-streamer display name

Viewers can type a custom name shown to the streamer instead of
their Google account name. It's saved per (streamer, viewer) pair
in SQLite and pre-filled on future visits to the same send link.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

server.js

@@ -7,7 +7,13 @@ const { createServer } = require('http');
 const { Server } = require('socket.io');
 const { OAuth2Client } = require('google-auth-library');
 const { execFile } = require('child_process');
-const { findStreamerByOverlayToken, findStreamerBySenderToken, getOrCreateStreamerByGoogle } = require('./db');
+const {
+  findStreamerByOverlayToken,
+  findStreamerBySenderToken,
+  getOrCreateStreamerByGoogle,
+  getViewerName,
+  setViewerName,
+} = require('./db');
 
 const PORT = process.env.PORT || 3000;
 const GOOGLE_CLIENT_ID = process.env.GOOGLE_CLIENT_ID;
@@ -113,6 +119,16 @@ app.get('/api/dashboard', requireAuth, (req, res) => {
   });
 });
 
+app.get('/api/viewer-name', requireAuth, (req, res) => {
+  const streamer = findStreamerBySenderToken(req.query.token);
+  if (!streamer) {
+    return res.status(404).json({ error: 'unknown link' });
+  }
+  const user = req.session.user;
+  const name = getViewerName(streamer.id, user.id) || user.name;
+  res.json({ name });
+});
+
 app.get('/overlay/:token', (req, res) => {
   res.sendFile(path.join(__dirname, 'public', 'overlay.html'));
 });
@@ -159,7 +175,7 @@ io.on('connection', (socket) => {
     console.log(`[socket] disconnected id=${socket.id} reason=${reason}`);
   });
 
-  socket.on('send_message', ({ token: senderToken, text } = {}) => {
+  socket.on('send_message', ({ token: senderToken, text, name } = {}) => {
     const streamer = findStreamerBySenderToken(senderToken);
     if (!streamer) {
       socket.emit('send_error', 'Unknown link');
@@ -183,11 +199,14 @@ io.on('connection', (socket) => {
       }
 
       const message = text.trim().slice(0, 500);
+      const displayName = (typeof name === 'string' && name.trim().slice(0, 60)) || user.name;
+      setViewerName(streamer.id, user.id, displayName);
+
       const room = `streamer-${streamer.id}`;
-      console.log(`[broadcast] streamer=${streamer.id} "${message}"`);
+      console.log(`[broadcast] streamer=${streamer.id} from="${displayName}" "${message}"`);
       io.to(room).emit('display_message', {
         text: message,
-        from: user.name,
+        from: displayName,
         at: Date.now(),
       });