docs: adopt SysOps Agent public identity

[PatrickDev-it]

Summary

• align public product identity with the renamed repository
• rename the Python distribution and primary CLI to sysops-agent
• retain sistemista as a temporary alpha compatibility alias
• update repository URLs, badges, clone path, security policy, contribution guide and NOTICE
• record the rename and validation evidence in Sinapsi handoff state

Validation

• Ruff check and format: green
• Mypy: zero errors
• pytest: 713 passed, 3 skipped
• isolated wheel/sdist: sysops_agent-0.1.0a1 built successfully