TUI persistence after execution

[sn]

This pull request updates the TUI (text user interface) experience in ntask to improve usability and error handling, and adds comprehensive tests for the new behavior. The TUI now persists after execution so users can review results, and can be dismissed with q, esc, or ctrl+c. Error messages and summaries are clearly shown in the footer with dismissal hints. Version numbers are also bumped to reflect these changes.

TUI Usability Improvements:

• The TUI now remains open after task execution, allowing users to review the DAG state and summary; users must explicitly dismiss the interface using q, esc, or ctrl+c (src/ntask/_cli.py, src/ntask/_render/tui.py). [1] [2]
• The footer now displays a summary or error message along with a hint to press q/esc to quit, improving clarity for users (src/ntask/_render/tui.py). [1] [2]

Error Handling Enhancements:

• Errors encountered during execution are now shown in the TUI footer with a clear dismissal hint, rather than immediately closing the app (src/ntask/_cli.py, src/ntask/_render/tui.py). [1] [2]

Testing and Reliability:

• Added tests to verify that the TUI footer displays correct quit hints, that errors are shown in the footer, and that the TUI only closes when the user explicitly dismisses it (tests/test_render_tui.py).

Versioning:

• Bumped the package version to 1.1.0 in both pyproject.toml and src/ntask/__init__.py to reflect the new features and improvements. [1] [2]