fix(admin-web/image-webp): bundle jsquash wasm via vite resolver

Vite 在生产构建里没法解析 @jsquash/webp 自带的相对 wasm 路径，导致 WebP 编码
首次调用就失败。改成直接 import encode.js + ?url 的 wasm 资源，并在 vite.config
里把 specifier 显式 alias 到 node_modules 的真实文件，运行前再调用 init({locateFile})
告诉 wasm 加载器去拿打包后的 URL。

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

apps/admin-web/src/lib/image-webp.ts

@@ -1,4 +1,6 @@
-import { encode } from "@jsquash/webp";
+import encode, { init as initWebpEncoder } from "@jsquash/webp/encode.js";
+import webpEncoderWasmUrl from "@jsquash/webp/codec/enc/webp_enc.wasm?url";
+import webpEncoderSimdWasmUrl from "@jsquash/webp/codec/enc/webp_enc_simd.wasm?url";
 import { reactive, readonly } from "vue";
 
 // upload limit set to 10MB
@@ -54,6 +56,30 @@ const imageUploadProgressState = reactive<ImageUploadProgressState>({
 });
 
 let activeProgressToken = 0;
+let webpEncoderReady: Promise<unknown> | null = null;
+
+function ensureWebpEncoderReady(): Promise<unknown> {
+  if (webpEncoderReady) {
+    return webpEncoderReady;
+  }
+
+  const ready = initWebpEncoder({
+    locateFile(path: string) {
+      if (path === "webp_enc_simd.wasm") {
+        return webpEncoderSimdWasmUrl;
+      }
+      if (path === "webp_enc.wasm") {
+        return webpEncoderWasmUrl;
+      }
+      return path;
+    },
+  }).catch((error: unknown) => {
+    webpEncoderReady = null;
+    throw error;
+  });
+  webpEncoderReady = ready;
+  return ready;
+}
 
 function ensureWebpFileName(fileName: string, fallbackBaseName = "image"): string {
   const trimmed = fileName.trim();
@@ -200,6 +226,7 @@ export async function convertImageFileToWebp(file: File): Promise<File> {
 
     const imageData = await createImageDataFromBlob(file, token);
     updateImageUploadProgress(token, { percent: 72, stage: "encoding" });
+    await ensureWebpEncoderReady();
     const encoded = await encode(imageData, { quality: 82 });
 
     updateImageUploadProgress(token, { percent: 88, stage: "finishing" });