Add preview card with modal for pasted long content in PromptInput

[shloimy-wiesel]

Currently, when pasting long text into PromptInput, the entire content is displayed inline, which can make the input area unwieldy.

Expected behavior:
Long pasted content should be displayed as a compact preview card (similar to Claude.ai and v0.app), showing:

• A truncated preview of the content
• File size and line count
• A "PASTED" badge/indicator
• Clicking the card opens a modal/dialog with the full content
• Modal should include actions to copy or download the pasted content

Current behavior:
All pasted text appears directly in the textarea, regardless of length.

Screenshots:

Suggested implementation:
Add a PromptInputPastedContent component that detects large pastes (e.g., >200 characters or >10 lines) and displays them as a clickable preview card above the textarea. The card should trigger a modal/dialog showing the full content with copy and download actions.

[unclebay143]

I'll be checking this out @haydenbleasel