[KKranthi6881]

Summary

• Bootstrap sqlmesh-spec-kit as a SQLMesh-native Python package and CLI.
• Add lifecycle, spec, SQLMesh project, doctor, report, Jira, and Confluence support.
• Add templates, commands, agents, skills, presets, docs, examples, CI, and Trusted Publishing release workflow.

Verification

• uv run --extra dev ruff check src tests
• uv run --extra dev mypy src tests
• uv run --extra dev pytest
• uv run --extra dev python -m build --sdist --wheel
• uv run --extra dev python -m twine check dist/*
• sdist forbidden-path check