chore(ts7): adopt the TypeScript 7 native compiler (tsgo)

Make the editor packages compatible with, and benefit from, the native Go
compiler (TypeScript 7 / tsgo) while keeping the npm publish path on stable tsc.

- Add @typescript/native-preview (pinned 7.0.0-dev.20260624.1). tsgo coexists
  with typescript@6, which Next typegen and the IDE plugin still need until the
  TS 7.1 programmatic API ships.
- Fix two react-three-fiber JSX augmentations the native checker rejects but
  tsc tolerated:
  - viewer: map only LineBasicNodeMaterial (the one webgpu node material used as
    a JSX tag) instead of the whole three/webgpu namespace (TS2320/TS2590).
  - plane-box-select-tool: drop the redundant `IntrinsicElements extends
    ThreeElements` block — it duplicated R3F's global augmentation and, by
    referencing @react-three/fiber's ThreeElements directly, hit a bun peer-dep
    variant-directory duplicate under tsgo (TS2320). r3f.d.ts already covers
    those JSX intrinsics. Types-only — no runtime change.
- check-types -> tsgo --noEmit (editor, @repo/ui, editor app, ifc-converter app)
- emit-package dev watch -> tsgo --build --watch
- build/publish stay tsc --build (prepublishOnly + release.yml unchanged;
  emitted .d.ts is byte-identical to tsc output)
- bump next 16.2.6 -> 16.2.9

tsc remains the source of truth and fallback. Published artifacts unchanged.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

packages/viewer/package.json

@@ -18,7 +18,7 @@
   ],
   "scripts": {
     "build": "tsc --build",
-    "dev": "tsc --build --watch",
+    "dev": "tsgo --build --watch",
     "prepublishOnly": "npm run build"
   },
   "peerDependencies": {

packages/viewer/src/components/viewer/index.tsx

@@ -7,7 +7,7 @@ import {
   sceneRegistry,
   useScene,
 } from '@pascal-app/core'
-import { Canvas, extend, type ThreeToJSXElements, useFrame, useThree } from '@react-three/fiber'
+import { Canvas, extend, type ThreeElement, useFrame, useThree } from '@react-three/fiber'
 import {
   forwardRef,
   useEffect,
@@ -38,7 +38,15 @@ import { SelectionManager } from './selection-manager'
 import { ViewerCamera } from './viewer-camera'
 
 declare module '@react-three/fiber' {
-  interface ThreeElements extends ThreeToJSXElements<typeof THREE> {}
+  // The TS 7 native compiler (tsgo) rejects mapping the entire `three/webgpu`
+  // namespace into JSX — `ThreeToJSXElements<typeof THREE>` triggers a TS2320
+  // heritage conflict with R3F's core-three base plus a TS2590 "union too
+  // complex". tsc 6 tolerates it; tsgo does not. R3F's base ThreeElements
+  // already covers core three, so we extract only the webgpu/TSL node materials
+  // we actually use as JSX (see r3f.docs.pmnd.rs/api/typescript).
+  interface ThreeElements {
+    lineBasicNodeMaterial: ThreeElement<typeof THREE.LineBasicNodeMaterial>
+  }
 }
 
 extend(THREE as any)