render2d im Browser: WASM/WebGPU-Viewport hinter ?engine=wasm

Integrations-Spike: die native 2D-Engine (src-tauri/render2d) laeuft jetzt als
WASM/WebGPU-Canvas in der App-UI, mit derselben Szene (planToRenderScene) und
ViewBox wie der WebGL2-Pfad; das SVG-Overlay (Text/Griffe/Auswahl) bleibt drueber.

- render2d: neues Feature "web" (wasm-bindgen/web-sys), Fassade WebPlanRenderer
  (new/set_scene/set_view_box/set_paper_scale/resize/render) auf Canvas-Surface.
  Geteilte GPU-Schicht (gpu.rs), native Fensterschicht (winit) unberuehrt.
- Font: cosmic-text findet auf wasm keine Systemfonts -> Inter-Bytes eingebettet
  (assets/Inter.ttf), Renderer.load_font + text_family aus der geladenen Familie.
- Frontend: useWasmPlanRenderer (gleiche Schnittstelle wie useGlPlanRenderer);
  PlanView waehlt die Engine per ?engine=wasm + navigator.gpu, sonst WebGL2/SVG.
- Build: npm-Script build:engine (wasm-pack, target web -> src/engine/pkg,
  gitignored). chromium-shell.sh mit WebGPU-Flags (--enable-unsafe-webgpu/Vulkan).
- Kompat-Shim: wgpu 22 sendet das spec-entfernte Limit maxInterStageShaderComponents,
  das neuere Chromium ablehnen -> im Hook vor requestDevice entfernt.

Verifiziert: cargo test -p render2d gruen (18), tsc gruen, wasm-Build gruen;
Headless-Chromium (?engine=wasm) zeichnet den Grundriss (Waende/Schraffur/
Tuerschwenk/Treppe/Raumtext) im WASM-Viewport, Fallback ohne Flag unveraendert.

package-lock.json

@@ -31,7 +31,8 @@
         "puppeteer": "^25.2.1",
         "typescript": "^5.6.2",
         "vite": "^5.4.8",
-        "vitest": "^4.1.9"
+        "vitest": "^4.1.9",
+        "wasm-pack": "^0.15.0"
       }
     },
     "node_modules/@babel/code-frame": {
@@ -750,6 +751,19 @@
         "node": ">=12"
       }
     },
+    "node_modules/@isaacs/fs-minipass": {
+      "version": "4.0.1",
+      "resolved": "https://registry.npmjs.org/@isaacs/fs-minipass/-/fs-minipass-4.0.1.tgz",
+      "integrity": "sha512-wgm9Ehl2jpeqP3zw/7mo3kRHFp5MEDhqAdwy1fTGkHAwnkGOVsgpvQhL8B5n1qlb01jV3n/bI0ZfZp5lWA1k4w==",
+      "dev": true,
+      "license": "ISC",
+      "dependencies": {
+        "minipass": "^7.0.4"
+      },
+      "engines": {
+        "node": ">=18.0.0"
+      }
+    },
     "node_modules/@jridgewell/gen-mapping": {
       "version": "0.3.13",
       "resolved": "https://registry.npmjs.org/@jridgewell/gen-mapping/-/gen-mapping-0.3.13.tgz",
@@ -2206,6 +2220,16 @@
         "node": ">=18"
       }
     },
+    "node_modules/chownr": {
+      "version": "3.0.0",
+      "resolved": "https://registry.npmjs.org/chownr/-/chownr-3.0.0.tgz",
+      "integrity": "sha512-+IxzY9BZOQd/XuYPRmrvEVjF/nqj5kgT4kEq7VofrDoM1MxoRjEWkrCC3EtLi59TVawxTAn+orJwFQcrqEN1+g==",
+      "dev": true,
+      "license": "BlueOak-1.0.0",
+      "engines": {
+        "node": ">=18"
+      }
+    },
     "node_modules/chromium-bidi": {
       "version": "16.0.1",
       "resolved": "https://registry.npmjs.org/chromium-bidi/-/chromium-bidi-16.0.1.tgz",
@@ -2986,6 +3010,29 @@
       "dev": true,
       "license": "MIT"
     },
+    "node_modules/minipass": {
+      "version": "7.1.3",
+      "resolved": "https://registry.npmjs.org/minipass/-/minipass-7.1.3.tgz",
+      "integrity": "sha512-tEBHqDnIoM/1rXME1zgka9g6Q2lcoCkxHLuc7ODJ5BxbP5d4c2Z5cGgtXAku59200Cx7diuHTOYfSBD8n6mm8A==",
+      "dev": true,
+      "license": "BlueOak-1.0.0",
+      "engines": {
+        "node": ">=16 || 14 >=14.17"
+      }
+    },
+    "node_modules/minizlib": {
+      "version": "3.1.0",
+      "resolved": "https://registry.npmjs.org/minizlib/-/minizlib-3.1.0.tgz",
+      "integrity": "sha512-KZxYo1BUkWD2TVFLr0MQoM8vUUigWD3LlD83a/75BqC+4qE0Hb1Vo5v1FgcfaNXvfXzr+5EhQ6ing/CaBijTlw==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "minipass": "^7.1.2"
+      },
+      "engines": {
+        "node": ">= 18"
+      }
+    },
     "node_modules/mitt": {
       "version": "3.0.1",
       "resolved": "https://registry.npmjs.org/mitt/-/mitt-3.0.1.tgz",
@@ -3577,6 +3624,33 @@
         "url": "https://github.com/fontello/svg2ttf?sponsor=1"
       }
     },
+    "node_modules/tar": {
+      "version": "7.5.19",
+      "resolved": "https://registry.npmjs.org/tar/-/tar-7.5.19.tgz",
+      "integrity": "sha512-4LeEWl96twnS2Q7Bz4MGqgazLqO+hJN63GZxXoIqh1T3VweYD997gbU1ItNsQafqqXTXd5WFyFdReLtwvRBNiw==",
+      "dev": true,
+      "license": "BlueOak-1.0.0",
+      "dependencies": {
+        "@isaacs/fs-minipass": "^4.0.0",
+        "chownr": "^3.0.0",
+        "minipass": "^7.1.2",
+        "minizlib": "^3.1.0",
+        "yallist": "^5.0.0"
+      },
+      "engines": {
+        "node": ">=18"
+      }
+    },
+    "node_modules/tar/node_modules/yallist": {
+      "version": "5.0.0",
+      "resolved": "https://registry.npmjs.org/yallist/-/yallist-5.0.0.tgz",
+      "integrity": "sha512-YgvUTfwqyc7UXVMrB+SImsVYSmTS8X/tSrtdNZMImM+n7+QTriRXyXim0mBrTXNeqzVF0KWGgHPeiyViFFrNDw==",
+      "dev": true,
+      "license": "BlueOak-1.0.0",
+      "engines": {
+        "node": ">=18"
+      }
+    },
     "node_modules/text-segmentation": {
       "version": "1.0.3",
       "resolved": "https://registry.npmjs.org/text-segmentation/-/text-segmentation-1.0.3.tgz",
@@ -3968,6 +4042,23 @@
         }
       }
     },
+    "node_modules/wasm-pack": {
+      "version": "0.15.0",
+      "resolved": "https://registry.npmjs.org/wasm-pack/-/wasm-pack-0.15.0.tgz",
+      "integrity": "sha512-DdqtGWc3+iFx+7lL7QU5LBWs7qMnwQSWxF0htSfE15sNa3roVwHjAkTm2JXgueU2GGfSwNqbq2EzyC2b/biKDA==",
+      "dev": true,
+      "hasInstallScript": true,
+      "license": "MIT OR Apache-2.0",
+      "dependencies": {
+        "tar": "^7.5.3"
+      },
+      "bin": {
+        "wasm-pack": "run.js"
+      },
+      "engines": {
+        "node": ">=16"
+      }
+    },
     "node_modules/webdriver-bidi-protocol": {
       "version": "0.4.2",
       "resolved": "https://registry.npmjs.org/webdriver-bidi-protocol/-/webdriver-bidi-protocol-0.4.2.tgz",