Avoid full replot on card resize

[rosenrot00]

• replace the ResizeObserver's full plot() path with a lightweight Plotly.relayout() for changed automatic dimensions
• skip resize work when the measured size is unchanged or the card is hidden
• preserve explicitly configured layout.width and layout.height
• keep the full render path as a fallback when an automatic dimension is removed

Every ResizeObserver notification currently calls plot({ should_fetch: false }). Although it does not fetch history, it still merges and evaluates the full configuration, processes cached data, and calls Plotly.react().

Plotly.Plots.resize() cannot be used for the common card layout because Plotly deliberately treats it as a no-op when both layout width and height are set. Updating only the changed dimensions through Plotly.relayout() avoids rebuilding traces while preserving the existing explicit sizing behavior.

This PR is independent of #634.