fix(tui): add Alt+V as fallback keybind for image paste on Windows Terminal

[pirrozani]

Issue for this PR

Closes #13800, #10154
Related issues: #13322, #12075
Related unmerged PRs from other contributors: #13161, #13871, #8626

Type of change

• Bug fix

What does this PR do?

On Windows Terminal, Ctrl+V is intercepted by the terminal before the TUI's onKeyDown fires. When the clipboard has only an image, Windows Terminal sends nothing — so the existing clipboard image read path never triggers.

Adds alt+v as a second default for input_paste ("ctrl+v,alt+v"). Windows Terminal doesn't intercept Alt+V, so it reaches onKeyDown and the existing PowerShell clipboard read works as intended.

Safe cross-platform: @opentui/core blocks character insertion when key.meta is true, so Alt+V with no image in clipboard does nothing. On macOS/Linux where Ctrl+V already passes through, it's a harmless extra binding.

How did you verify your code works?

Tested on Windows 11 + Windows Terminal. Alt+V with an image in clipboard inserts [Image 1] in the prompt. Ctrl+V text paste unaffected.

Screenshots / recordings

Checklist

• I have tested my changes locally
• I have not included unrelated changes in this PR

[github-actions]

The following comment was made by an LLM, it may be inaccurate:

Based on my search, I found several related PRs that may be duplicates or closely related to PR #17539:

Potential Duplicates/Related PRs:

1. fix: add alt+v keybind for pasting images #8495 - "fix: add alt+v keybind for pasting images"

   • Directly addresses the same Alt+V keybind solution for image pasting

2. fix(tui): make Windows image paste reliable #13161 - "fix(tui): make Windows image paste reliable"

   • Mentioned in the current PR as a related unmerged PR; addresses Windows image paste reliability

3. fix: handle text clipboard paste on Ctrl+V for Windows terminals #13871 - "fix: handle text clipboard paste on Ctrl+V for Windows terminals"

   • Mentioned in the current PR as a related unmerged PR; addresses Ctrl+V clipboard paste on Windows

4. fix(tui): fix Ctrl+V paste on Windows/WSL2 (#6560 and #8209) #8626 - "fix(tui): fix Ctrl+V paste on Windows/WSL2"

   • Mentioned in the current PR as a related unmerged PR; addresses Ctrl+V paste issues on Windows/WSL2

5. fix(tui): support clipboard image paste with proper filename on WSL2 #8209 - "fix(tui): support clipboard image paste with proper filename on WSL2"

   • Related to clipboard image paste functionality on Windows environments

These PRs all relate to the same underlying issue: clipboard image paste on Windows Terminal/environments. PR #8495 appears to be the most directly related as it also implements the Alt+V keybind solution.

[pirrozani]

PR #8495 does exactly the same (did not find that earlier), so i am closing this PR.