Add Jira bridge workflow

[KKranthi6881]

Summary

• add dbt-specify jira pull/attach/create-tasks/sync commands
• generate local spec drafts from Jira issues with jira.yml traceability
• attach approved artifacts and create idempotent Jira subtasks from tasks.md
• add Jira integration docs, tutorial, tests, and bump package version to 1.3.0

Checks

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