fix: cache render model loading

[ktk-research-9185]

Summary

• add shared in-flight/completed caching for load3DModel in the render/SVG utility path
• normalize cache keys by removing only cachebust_origin while preserving meaningful query params and hashes
• pass explicit model formats from renderComponent so extensionless EasyEDA/CDN download URLs still load through the correct loader
• return cloned model instances with cloned materials so per-render mutations do not leak into the cached template

Verification

• npx @biomejs/biome@2.1.4 format src/utils/load-model.ts src/utils/render-component.tsx tests/load-model.test.ts
• git diff --check
• npm run build (blocked locally: npm install fails while extracting node_modules/three with TAR_ENTRY_ERROR in this Google Drive workspace, so tsup is unavailable)

/claim #93

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Project	Deployment	Actions	Updated (UTC)
3d-viewer	Ready	Preview, Comment	May 21, 2026 11:35am

[MikeGarciaAGM]

Looks good to me.