warnings to become callouts

Components from the wigglystuff library have been promoted into marimo core as of version 0.20.0, including the matrix, pytorch, and chart-select widgets. To handle deprecation gracefully, a helper function detects whether code is running inside marimo (vs. Jupyter) and renders a styled HTML callout with a clickable link instead of a plain Python warning, taking advantage of the fact that marimo always runs in a browser context.