[Arc] Clippath and Gradient for canvas

Gauge Example

canvas layer does not to clip or show gradient.

I think it's 2 fold... 1 issue is similar to what we recently added GeoClipPath as supporting the clip snippet for ClipPath is a little tricky for Canvas...

{#snippet clip()} {/snippet}

we might need to ArcClipPath (although I hate to keep adding a ClipPath for every shape :)). Might be a way to hook into the rendering call of Arc and bubble up to ClipPath...
also, gradients in Canvas are a little tricky as they don't have the concept of objectBoundingBox and gets tricky to great "relative" gradients (not just global) - https://github.com/techniq/layerchart/blob/next/packages/layerchart/src/lib/components/LinearGradient.svelte#L163-L171

Start with the Arc gauge example and the canvas rendering path, then compare the clipping approach discussed for GeoClipPath with the ClipPath snippet shown here. Read packages/layerchart/src/lib/components/LinearGradient.svelte at the referenced lines to understand the existing relative-gradient behavior. Done means the Arc canvas layer clips correctly and displays gradients in the gauge example.