Use Ctrl+V for clipboard image paste

[Drecullith]

Summary

The clipboard manager correctly puts selected images on the Wayland clipboard, but omarchy-clipboard-paste-file currently follows that with Shift+Insert.

Terminal emulators such as foot consume Shift+Insert as their own text-only paste action. Since an image clipboard entry has no text flavor, the terminal finds nothing to paste and the application running inside the terminal never receives the shortcut.

This changes the image/file paste helper to send Ctrl+V instead.

The text paste path is intentionally unchanged: Omarchy's existing text helpers continue to use Shift+Insert where appropriate for terminal-safe text paste.

Fixes #10526.

Testing

Added test/shell.d/clipboard-file-paste-test.sh covering:

• image bytes remain unchanged when copied
• the image MIME type is preserved
• normal image paste sends Ctrl+V
• --copy-only still sends no synthetic paste shortcut

The reported affected setup has also confirmed manually that Ctrl+V successfully delivers the staged image to an image-aware terminal application.