Extract Vue frontend into separate container and add stp_wasm crate

Move Vue app from nginx/vue/ to top-level vue/ with its own Dockerfile,
update docker-compose configs and nginx proxy to serve from the new
container, and add initial Rust WASM crate (stp_wasm). Also fix .gitignore
to exclude Rust target/ directories.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

vue/package.json

@@ -0,0 +1,33 @@
+{
+  "name": "nginx-html",
+  "version": "0.0.0",
+  "private": true,
+  "type": "module",
+  "engines": {
+    "node": "^20.19.0 || >=22.12.0"
+  },
+  "scripts": {
+    "dev": "vite",
+    "build": "vite build",
+    "preview": "vite preview"
+  },
+  "dependencies": {
+    "@mdit/plugin-katex": "^0.24.1",
+    "@tailwindcss/vite": "^4.1.18",
+    "@vueuse/core": "^14.2.1",
+    "axios": "^1.13.2",
+    "katex": "^0.16.27",
+    "markdown-it": "^14.1.0",
+    "markdown-it-wikilinks": "^1.4.0",
+    "pinia": "^3.0.4",
+    "tailwindcss": "^4.1.18",
+    "typescript": "^5.9.3",
+    "vue": "^3.5.22",
+    "vue-router": "^4.6.3"
+  },
+  "devDependencies": {
+    "@vitejs/plugin-vue": "^6.0.1",
+    "vite": "^7.1.11",
+    "vite-plugin-vue-devtools": "^8.0.3"
+  }
+}