Multi-tenant platform: per-streamer overlay/sender links + CI/CD

Streamers log in with Google on a new landing page and get a
dashboard with two auto-generated, permanent links: one for their
OBS/StreamLabs Browser Source, one to share with viewers. Messages
are now scoped to the right streamer via Socket.IO rooms instead of
broadcasting globally. Streamer records and tokens are persisted in
SQLite (node:sqlite) so links survive restarts/redeploys.

Also adds a Forgejo Actions pipeline mirroring t2sTelegramBot's:
build, smoke-test, push to the local registry, then deploy to the
prod host over SSH.

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

docker-compose.yml

@@ -1,10 +1,11 @@
 services:
   app:
     build: .
+    image: 192.168.8.174:3000/vrubel/send2streamer:latest
+    container_name: send2streamer
     ports:
       - "3000:3000"
-    environment:
-      - PORT=3000
-      - GOOGLE_CLIENT_ID=${GOOGLE_CLIENT_ID}
-      - SESSION_SECRET=${SESSION_SECRET}
+    env_file: .env
+    volumes:
+      - ./data:/app/data
     restart: unless-stopped