docs: document Python >=3.12 requirement bump in release notes

[cagataycali]

Context

PR #83 bumps requires-python from >=3.10 to >=3.12. This is a breaking change for users on Python 3.10/3.11.

Action Items

• Add release notes entry explaining the breaking change and rationale (lerobot >=0.5 requires 3.12)
• Document how to run coverage manually: uv run pytest --cov=strands_robots tests/ (since --cov was removed from default pytest addopts)

Related

• PR chore: modernize build system — uv lockfile, Python >=3.12 #83
• Review comment from @awsarron