This example keeps an SVG with SMIL animation hidden under the map, snapshots each frame into a canvas, and feeds it into a MapLibre StyleImageInterface. Use this pattern when you need a pulsing/glowing marker that’s authored entirely in SVG.

• No changes to registerSVGProtocol; animation happens via a custom helper.
• Frames are sampled at 30fps and uploaded with map.addImage().
• When the map is removed, the hidden SVG and timers are cleaned up.