fix: support image processing on CPUs without x86-64-v2

tests/sharp-fallback.test.mjs

@@ -0,0 +1,26 @@
+import assert from 'node:assert/strict';
+import { spawnSync } from 'node:child_process';
+import test from 'node:test';
+
+test('image processing falls back to WebAssembly without native CPU support', () => {
+  // Isolate the native-binding simulation from the rest of the test process.
+  const result = spawnSync(process.execPath, ['-e', `
+    const Module = require('node:module');
+    const original = Module._load;
+    Module._load = function (id, ...args) {
+      if (id.endsWith('.node') && !id.includes('wasm32')) {
+        const error = new Error('Simulated unavailable native binding');
+        error.code = 'MODULE_NOT_FOUND';
+        throw error;
+      }
+      return original.call(this, id, ...args);
+    };
+    const sharp = require('sharp');
+    (async () => {
+      const image = await sharp({ create: { width: 8, height: 8, channels: 3, background: '#336699' } }).webp().toBuffer();
+      const metadata = await sharp(image).metadata();
+      if (metadata.format !== 'webp' || metadata.width !== 8 || metadata.height !== 8) throw new Error('Image round trip failed');
+    })().catch(error => { console.error(error); process.exitCode = 1; });
+  `], { encoding: 'utf8', timeout: 30000 });
+  assert.equal(result.status, 0, result.stderr || result.error?.message);
+});