Closes #42972


https://github.com/user-attachments/assets/98f2d3dc-5682-4670-b636-fa8ea2495c69

Release Notes:

- Added automatic file context detection when pasting code into the AI
agent panel. Pasted code now displays as collapsible badges showing the
file path and line numbers (e.g., "app/layout.tsx (18-25)").

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Co-authored-by: Bennet Bo Fenner <bennetbo@gmx.de>