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/vite.config.js

@@ -0,0 +1,28 @@
+import { fileURLToPath, URL } from "node:url";
+
+import { defineConfig } from "vite";
+import tailwindcss from "@tailwindcss/vite";
+import vue from "@vitejs/plugin-vue";
+import vueDevTools from "vite-plugin-vue-devtools";
+
+// https://vite.dev/config/
+export default defineConfig({
+    plugins: [
+        vue(),
+        ...(process.env.NODE_ENV !== "production" ? [vueDevTools()] : []),
+        tailwindcss(),
+    ],
+    resolve: {
+        alias: {
+            "@": fileURLToPath(new URL("./src", import.meta.url)),
+        },
+    },
+    server: {
+        host: "0.0.0.0",
+        proxy: {
+            "/api": "http://localhost:8080",
+            "/gitea": "http://localhost:3000",
+            "/radio": "http://localhost:8000",
+        },
+    },
+});