Initial commit: overlay + sender pages for StreamLabs browser source

Express + Socket.IO backend with Google login on the sender page,
a transparent overlay page for OBS/StreamLabs Browser Source, and
TTS voice-over via the edge-tts Python CLI (same engine as
t2sTelegramBot). Dockerized for deployment.

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

Dockerfile

@@ -0,0 +1,16 @@
+FROM node:22-alpine
+
+RUN apk add --no-cache python3 py3-pip && \
+    pip install --no-cache-dir --break-system-packages edge-tts
+
+WORKDIR /app
+
+COPY package.json package-lock.json* ./
+RUN npm ci --omit=dev
+
+COPY server.js ./
+COPY public ./public
+
+EXPOSE 3000
+
+CMD ["node", "server.js"]