Woodpecker CI/CD Agent

Woodpecker is a simple, yet powerful CI/CD engine with great extensibility.
This is the agent component that executes pipeline steps on behalf of the server.

The agent connects to a Woodpecker server and executes pipeline tasks in
Docker containers. Multiple agents can connect to a single server for
distributed builds.

Configuration:
- Set WOODPECKERSERVER to point to your Woodpecker server
- Set WOODPECKERAGENT_SECRET to match your server's agent secret
- Agent requires access to Docker to execute pipelines

See https://woodpecker-ci.org/docs for setup instructions.