feat: IFC → Pascal converter (package + app)

Brings the IFC-to-Pascal converter into the monorepo as a pure-logic
package plus a Next.js app, replacing the standalone repo that consumed
published @pascal-app/* packages (and drifted from their schemas).

packages/ifc-converter — pure conversion. Parses IFC via web-ifc and
maps elements onto @pascal-app/core node schemas (workspace-linked, so
no more version drift). Builds doors/windows, walls, slabs, columns,
roofs, stairs, sites/buildings/levels. Validates each node via the real
Zod schemas at build time (tryParse) and strips undefined metadata.

apps/ifc-converter — the UI: drop zone, example picker, element search,
JSON download, and a 3D preview rendered through the real
@pascal-app/viewer (registry bootstrap + read-only scene) with a custom
toolbar (camera/level/wall/grid/theme), level selector with
camera-focus, auto-fit, and selection bridged to an inspector.

Conversion specifics worth noting:
- Door/window vertical centering (height/2; windows + sill).
- Nearest-wall hosting fallback for files lacking IFCRELFILLSELEMENT,
  preferring walls long enough to contain the opening and clamping the
  along-wall position so cutouts can't overflow and break wall CSG.
- Plain IFCWALL (Brep/mapped geometry) falls back to default
  height/thickness instead of collapsing to zero-height slivers.
- Columns convert as plain structural shafts (no decorative
  base/capital) sized from the IFC profile.
- Beams + items are skipped for now (no Pascal beam type; items need a
  catalog asset) — counted in the conversion summary.

Large example IFCs are fetched from a public bucket at runtime; the four
small ones are committed. web-ifc.wasm is copied into public/ on
install/dev/build. README flags early-alpha + invites contributions.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

apps/ifc-converter/scripts/copy-web-ifc-wasm.mjs

@@ -0,0 +1,56 @@
+#!/usr/bin/env node
+// web-ifc ships its WASM binaries inside node_modules. Next.js needs to
+// serve them at the app root URL (the library hardcodes `/web-ifc.wasm`
+// when no `wasmPath` override is set), so copy the three blobs into
+// `public/` so they're served from /web-ifc*.wasm.
+//
+// Run on `postinstall` and again on `predev` / `prebuild` so a forgotten
+// install step doesn't leave the dev server with a stale or missing
+// copy. Idempotent: skips files that already match by size.
+
+import { copyFileSync, existsSync, mkdirSync, statSync } from 'node:fs'
+import { join, resolve } from 'node:path'
+
+// web-ifc's package.json doesn't expose subpath exports, so we can't use
+// require.resolve('web-ifc/package.json'). Walk up the script directory
+// looking for the package folder inside any node_modules along the way.
+function findWebIfcDir(startDir) {
+  let dir = startDir
+  while (dir && dir !== '/') {
+    const candidate = join(dir, 'node_modules', 'web-ifc')
+    if (existsSync(join(candidate, 'web-ifc.wasm'))) return candidate
+    dir = resolve(dir, '..')
+  }
+  return null
+}
+
+const webIfcDir = findWebIfcDir(import.meta.dirname)
+if (!webIfcDir) {
+  console.warn('[ifc-converter] web-ifc package not found — wasm copy skipped.')
+  process.exit(0)
+}
+const publicDir = join(import.meta.dirname, '..', 'public')
+
+mkdirSync(publicDir, { recursive: true })
+
+const files = ['web-ifc.wasm', 'web-ifc-mt.wasm', 'web-ifc-node.wasm']
+for (const name of files) {
+  const src = join(webIfcDir, name)
+  const dst = join(publicDir, name)
+  try {
+    const srcSize = statSync(src).size
+    let dstSize = 0
+    try {
+      dstSize = statSync(dst).size
+    } catch {
+      /* not present yet */
+    }
+    if (srcSize === dstSize) {
+      continue
+    }
+    copyFileSync(src, dst)
+    console.log(`[ifc-converter] copied ${name} (${(srcSize / 1024).toFixed(0)} KB)`)
+  } catch (err) {
+    console.warn(`[ifc-converter] could not copy ${name}:`, err.message)
+  }
+}