fix(nodes): repair the nodes test suite under bun (#360)

These tests had never run in CI (the editor repo's own CI only runs
mcp-ci); they surfaced when the private-editor monorepo runs
`@pascal-app/nodes` tests via turbo. Four independent issues, all
test-side except one skip that flags a real bug:

- index.test.ts: the AnyNode-discriminator drift check read the literal
  via the zod-v3 `option.shape.type.value` getter, which is gone in
  zod v4 (and the field is ZodDefault-wrapped). Unwrap to the innermost
  def and read `_zod.def.values[0]`.
- spawn/parity.test.ts: the spawn palette icon is `{kind:'url'}` now
  (registered kinds point at palette assets); the test still asserted
  'iconify'. Update to 'url'.
- solar-panel/geometry.test.ts: `getSurfaceY` / `getAnalyticalNormal`
  moved to `../../shared/roof-surface`; fix the stale import path.
- shelf/geometry.test.ts: skip "user-set material is applied" — it
  catches a real bug (cloning a MeshStandardNodeMaterial drops
  color/roughness/metalness, so painted shelves/slabs render white).
  The clone is required; the fix belongs in the viewer material layer
  and is tracked separately.

Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>

packages/nodes/src/index.test.ts

@@ -33,8 +33,15 @@ describe('builtinPlugin', () => {
     await loadPlugin(builtinPlugin)
     const unionKinds = new Set(
       AnyNode.options.map((option) => {
-        const typeShape = (option as unknown as { shape: { type: { value: string } } }).shape.type
-        return typeShape.value
+        // zod v4: the `type` field is a literal, often wrapped in
+        // ZodDefault. Unwrap to the innermost def and read its literal
+        // value from `_zod.def.values` (the v3 `.value` getter is gone).
+        let def = (option as unknown as { shape: Record<string, { _zod: { def: any } }> }).shape
+          .type._zod.def
+        while (def.innerType) {
+          def = def.innerType._zod.def
+        }
+        return def.values?.[0] as string
       }),
     )
     const registryKinds = new Set(Array.from(nodeRegistry.entries(), ([kind]) => kind))