Paste a clip into the current app

[alvst]

What changed

• Adds a contextual Paste to Current App action whose label follows the frontmost application.
• Sends the selected clip through the standard paste path without adding an extra submit keystroke.

Why

The primary right-click action should make it clear where the clip will be pasted.

Validation

• swift build
• Manually exercised the contextual paste action in Demo mode