chore: release 5.0.0

[vinismarques]

Summary

• Bump package version from 4.0.0 to 5.0.0 in pyproject.toml, uv.lock, and README install instructions.

Included since 4.x

• Migrate project tooling and maestro-init scaffold to uv
• Load workers from files or modules; improve scaffold (incl. PyTorch base images)
• Expose worker hardware health metadata (NVML / MPS / MIG)
• Report deployed worker version in health
• Preserve fractional billable seconds
• Update framework dependencies and add code-quality tooling

Test plan

• Confirm version is 5.0.0 in pyproject.toml and uv.lock
• Confirm README install pin points at @5.0.0
• After merge/tag, verify pip install ...@5.0.0 resolves correctly