Add Dockerfile, compose file and Gitea Actions workflow

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

docker-compose.yml

@@ -0,0 +1,17 @@
+services:
+  audiobook-player:
+    image: git.necloud.us/nate/audiobook-player:latest
+    # build: .          # uncomment to build locally instead of pulling
+    container_name: audiobook-player
+    restart: unless-stopped
+    ports:
+      - "8080:8080"
+    environment:
+      OPENAUDIBLE_URL: http://172.16.16.106:8000
+      OPENAUDIBLE_USER: ${OPENAUDIBLE_USER}          # put these in a .env file next to this one
+      OPENAUDIBLE_PASSWORD: ${OPENAUDIBLE_PASSWORD}
+    volumes:
+      - player-data:/data    # accounts, sessions, listening progress
+
+volumes:
+  player-data: