Fix WASM RuntimeError causing persistent display failures in mesh worker

[Copilot]

Intermittent RuntimeError: index out of bounds from replicad's WASM module would corrupt the mesh worker's WASM heap, causing all subsequent geometry renders to silently fall back to "No output to display" — only recoverable via page refresh.

Root cause

geometryProvider.get() speculatively calls deserializeDrawing() on all cached shapes. When called on Shape3D data, the WASM runtime can trap (RuntimeError: index out of bounds), leaving the module in an unrecoverable state. Every deserialization after that also fails.

Changes

geometryProvider.ts

• Add WasmDeserializationError (exported) — thrown when both deserializeDrawing and deserializeShape fail, giving callers a precise signal to act on
• On double-deserializer failure, delete the corrupt IndexedDB entry via deleteShape() so geometry is recomputed on next request rather than failing indefinitely

meshWorker.ts

• Import WasmDeserializationError; detect WASM failures via instanceof WasmDeserializationError || e instanceof WebAssembly.RuntimeError
• Schedule self.close() in a finally block (after fallback attempt) using named constant WORKER_RESTART_DELAY_MS = 100ms — workerpool then spins up a fresh worker with a clean WASM heap
• Wrap fallback mesh generation in its own try/catch so uncached default-mesh edge cases propagate correctly

// geometryProvider.ts — thrown instead of generic Error
throw new WasmDeserializationError("Failed to deserialize geometry: " + e2);

// meshWorker.ts — triggers worker restart via finally
const isWasmError =
  e instanceof WasmDeserializationError ||
  e instanceof WebAssembly.RuntimeError;
try {
  return { id, mesh: await generateDefaultMesh(context) };
} catch (fallbackError) { ... throw e; }
finally {
  if (isWasmError) setTimeout(() => self.close(), WORKER_RESTART_DELAY_MS);
}

Effect: one render cycle shows the fallback; the next user action triggers a fresh worker that deserializes and renders correctly — no page refresh required.