refactor: extract scheduler to standalone repository

Scheduler service moved to git.schweitz.net/jpmschweitzer/scheduler
- Source code removed from this repository
- Stack file updated to use container image from Gitea registry
- Added Gitea Actions runner to gitea stack for CI/CD
- Documentation updated with external service reference

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

stacks/gitea.yml

@@ -48,6 +48,24 @@ services:
     networks:
       - docker-dataplane
 
+  gitea-runner:
+    image: gitea/act_runner:latest
+    container_name: gitea-runner
+    restart: unless-stopped
+    volumes:
+      - /var/run/docker.sock:/var/run/docker.sock
+      - /home/jpmschweitzer/docker-data/gitea/runner:/data
+    environment:
+      - CONFIG_FILE=/data/config.yaml
+      - GITEA_INSTANCE_URL=http://gitea:3000
+      - GITEA_RUNNER_REGISTRATION_TOKEN=${GITEA_RUNNER_TOKEN}
+      - GITEA_RUNNER_NAME=docker-runner
+      - TZ=Europe/Amsterdam
+    depends_on:
+      - gitea
+    networks:
+      - docker-dataplane
+
 networks:
   docker-dataplane:
     external: true