feat: Implement Dynamic Environment Orchestrator (DEO) for Elastic Scaling and Resilience

[RUFFY-369]

PR Type

• RL Environment PR - Complete Environment Snapshot & Zero-Training sections
• Non-Environment PR - Complete Description, Related Issues & Type of Change sections

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📝 General Information

Description

This PR implements the Dynamic Environment Orchestrator (DEO), a resilient control plane for managing elastic scaling of environment workers. The current static allocation model in atroposlib often leading to VRAM fragmentation or rollout starvation during high-variance RL workloads.

Technical Implementations:

• PID-Dampened Scaling: Implements a scaling controller with hysteresis to prevent "flapping" during transient throughput spikes.
• Resilient Execution: Uses os.setpgrp for process group isolation and logic to adopt orphaned child processes on startup, preventing resource leakage on GPU nodes.
• Graceful Draining: Adds SIGUSR1 signal handling across the environment stack, allowing workers to complete in-flight rollouts before exiting.
• Hardware Telemetry: Integration with nvidia-smi to cordon thermally throttled or memory-saturated GPUs during scale-up.
• API Expansion: Adds a /global-status endpoint to the Atropos server to expose real-time "Rollout Pressure" metrics.

Related Issues

It solves #437

Type of Change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update
• Code refactor (no functional changes)
• Build/CI/CD related changes
• Other (please describe):

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✅ Developer & Reviewer Checklist

• Code follows project style (black, isort, flake8 pass with pre-commit)
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• New and existing unit tests pass locally with my changes
• Docstrings added for all new public classes / functions
• If .env vars required, did you add it to the .env.example in repo root?