5fe0965297
Adds a capability check and an UnsupportedGpuViewerFallback so the viewer renders an informative panel instead of crashing on environments that expose neither WebGPU nor WebGL. Capability detection runs post-mount to stay hydration-safe, the renderer-init failure path swaps to the fallback, and the fallback signals scene-readiness so the host editor loader does not hang. Reworked from #403 (anton-pascal) onto current main; resolves the import conflict and the SSR/scene-ready gotchas surfaced in review. Co-authored-by: Open Pascal <open@pascal.app>