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>

packages/ifc-converter/README.md

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+# @pascal-app/ifc-converter
+
+Pure conversion logic for IFC → Pascal scene graphs. Takes a `Uint8Array` of
+IFC bytes, returns `{ nodes, rootNodeIds, stats }` shaped against
+`@pascal-app/core` schemas.
+
+No DOM, no React. The UI lives in `apps/ifc-converter`.

packages/ifc-converter/package.json

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+{
+  "name": "@pascal-app/ifc-converter",
+  "version": "0.1.0",
+  "description": "IFC → Pascal scene-graph conversion. Pure logic — no DOM, no React.",
+  "type": "module",
+  "main": "./dist/index.js",
+  "types": "./dist/index.d.ts",
+  "exports": {
+    ".": {
+      "types": "./dist/index.d.ts",
+      "import": "./dist/index.js",
+      "default": "./dist/index.js"
+    }
+  },
+  "files": [
+    "dist",
+    "README.md"
+  ],
+  "scripts": {
+    "build": "tsc --build",
+    "dev": "tsc --build --watch",
+    "test": "bun test",
+    "prepublishOnly": "npm run build"
+  },
+  "dependencies": {
+    "@pascal-app/core": "*",
+    "nanoid": "^5.1.6",
+    "web-ifc": "^0.0.77"
+  },
+  "devDependencies": {
+    "@pascal/typescript-config": "*",
+    "@types/bun": "^1.3.0",
+    "typescript": "6.0.2"
+  },
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/pascalorg/editor.git",
+    "directory": "packages/ifc-converter"
+  },
+  "license": "MIT",
+  "homepage": "https://github.com/pascalorg/editor/tree/main/packages/ifc-converter#readme",
+  "bugs": "https://github.com/pascalorg/editor/issues"
+}

packages/ifc-converter/tsconfig.json

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+{
+  "extends": "@pascal/typescript-config/react-library.json",
+  "compilerOptions": {
+    "outDir": "dist",
+    "rootDir": "src",
+    "noEmit": false,
+    "composite": true,
+    "incremental": true,
+    "types": ["bun"],
+    // Migrated from a repo without `noUncheckedIndexedAccess`. The
+    // existing index access patterns (Mat4 / IFC entity arrays) are
+    // surrounded by length checks the type system can't follow. Re-enable
+    // when the file is split into per-element modules.
+    "noUncheckedIndexedAccess": false
+  },
+  "include": ["src"],
+  "exclude": ["node_modules", "dist"]
+}