Reset model fallback boundary when model URLs change

[Zhenvip]

Summary

• Add a resetKey to ThreeErrorBoundary so captured loader errors can be cleared when the active model fallback source changes.
• Key the CAD model fallback error boundary by component id, fallback index, and the current GLTF/mesh/STEP URLs.
• Add focused regression coverage for reset behavior and URL-sensitive fallback keys.

Why

On current main, the fallback ThreeErrorBoundary is keyed only by component id and fallback index. If a model URL fails once and then changes to a valid replacement URL, the existing boundary can stay in its old error state and immediately skip/advance the new candidate instead of retrying that replacement model. That creates unnecessary fallback churn and can prevent recovered model loads from displaying.

/claim #93

Verification

• bun test tests/model-fallback-boundary.test.ts -> 3 pass
• npx biome check src/AnyCadComponent.tsx src/three-components/ThreeErrorBoundary.tsx tests/model-fallback-boundary.test.ts -> no fixes/errors
• npx tsc --noEmit --pretty false -> exit 0
• npm run build -> exit 0
• npm run test:node-bundle -> exit 0
• git diff --check -> exit 0

Full bun test currently reports 27 passing tests and 3 unrelated existing failures on this checkout:

• tests/preprocess-circuit-json.test.ts: faux-board z expectations are 0.1 higher than current output.
• tests/outline-bounds.test.ts: expected older soldermask color string does not match the current rendered SVG color.

AI-assisted with Codex; I reviewed the diff and local verification before submitting.

[vercel]

The latest updates on your projects. Learn more about Vercel for GitHub.

Project	Deployment	Actions	Updated (UTC)
3d-viewer	Ready	Preview, Comment	May 25, 2026 9:29pm

[CharlieLZ]

Additional review notes for the /claim #93 bounty:

• Vercel preview is available from the bot comment: https://3d-viewer-git-fork-zhenvip-codex-93-reset-mode-4c7e9c-tscircuit.vercel.app
• This is a narrow fallback lifecycle fix: the error boundary now resets only when the active model source changes, so a previously failed GLTF/OBJ/STEP fallback can retry a replacement URL instead of staying stuck in the old error state.
• Focused coverage is in tests/model-fallback-boundary.test.ts; local validation commands are listed in the PR body.

This should be non-overlapping with the earlier loader/cache fixes on #93 because it only targets boundary reset behavior after model URL changes.