Improving memory managemenet, testing and adding Justfile

[HackStrix]

This pull request introduces significant improvements to testing, memory management, and developer tooling for the herd project. It adds comprehensive unit, integration, and proxy tests, implements configurable memory limits for worker processes, and provides a Justfile for streamlined development workflows. The changes enhance code reliability, test coverage, and operational safety.

Testing Enhancements:

• Added extensive unit tests for ProcessFactory and worker behavior, covering process spawning, health checks, timeout handling, memory limits, and process cleanup (factory_test.go, worker_test.go). [1] [2]
• Introduced integration tests to verify end-to-end pool and proxy functionality with dummy worker processes (integration_test.go).
• Added dedicated proxy tests using a mock pool to ensure correct routing, error handling, and session management (proxy/proxy_test.go).

Memory Management:

• Implemented WithMemoryLimit in ProcessFactory, allowing a soft virtual memory limit to be set for worker processes (enforced via ulimit on Linux, no-op on macOS/unsupported platforms). Updated process spawning logic to use a shell wrapper when memory limits are specified (factory.go, examples/ollama/main.go). [1] [2] [3] [4]

Developer Tooling:

• Added a justfile with recipes for running tests (including race detection), linting, dependency tidying, coverage reporting, and a CI shortcut, improving developer experience and CI/CD integration.