tuiapp_v2.py: Copy and paste do not work in the TUI

[liuyuyan6100]

Description

I found that the new Textual-based TUI interface tuiapp_v2.py does not support normal copy and paste behavior in local testing.

This affects basic terminal interaction, especially when using the TUI for long prompts, multi-line command input, or copying generated output.

Affected File

• frontends/tuiapp_v2.py

Steps to Reproduce

1. Pull the latest code:

   git pull

2. Install Textual if needed:

   pip install textual

3. Run the new TUI from the project root:

   python frontends/tuiapp_v2.py

4. Try the following operations:

   • Paste text into the input area
   • Paste multi-line text into the input area
   • Select text from the TUI output area and copy it
   • Use common terminal copy/paste shortcuts

Expected Behavior

Copy and paste should work normally:

• Users should be able to paste single-line text into the input box
• Users should be able to paste multi-line text into the input box
• Users should be able to select and copy text from the TUI output area
• Existing TUI shortcuts should not block basic terminal copy/paste behavior

Actual Behavior

Copy and paste do not work as expected in tuiapp_v2.py.

In my testing, basic copy/paste behavior appears to be blocked or unavailable in the new TUI interface.

Impact

This significantly affects the usability of the new TUI, especially for:

• Long prompt input
• Multi-line text editing
• Copying generated responses
• Reusing command outputs
• Daily terminal-based workflows

Environment

• OS: Ubuntu 24.04.4 LTS
• Python: Python 3.12.3
• Textual: 8.2.5
• Shell: /bin/bash
• TERM: xterm
• SSH: yes
• tmux: no
• Local commit tested: 5b50eac

Additional Notes

The previous tuiapp.py does not appear to be affected in the same way.

Since tuiapp_v2.py was recently introduced as the new Textual-based interface, it would be great to ensure that copy/paste remains compatible with common terminal workflows.

I am reporting this after local verification and would be happy to help test a fix or submit a PR if the expected behavior is confirmed.

[szdtzpj]

Submitted draft PR #354 with a focused fix for this: #354

The change restores Ctrl+V paste in tuiapp_v2.py while keeping bracketed-paste newline normalization, long multi-line paste placeholders, and duplicate-paste protection.

Validation run locally:

• python -m unittest discover -s tests -p test*.py
• python -m py_compile frontends\tuiapp_v2.py frontends\stapp.py tests\test_tuiapp_v2_input.py
• python frontends\tuiapp_v2.py --help
• git diff --check