fix(wechat): rotate image_url-poisoned sessions for report follow-ups

Goose cannot persist historical image scrub (PUT 405), so DeepSeek rejects
image_url on the next turn. Reattach the recent report image and rotate to a
fresh session instead of treating the follow-up as a missing page source.

Co-authored-by: Cursor <cursoragent@cursor.com>

tkmind-proxy-vision.test.mjs

@@ -111,12 +111,14 @@ test('buildVisionPayload sends all current-turn images to Qwen in order', async
 
   assert.equal(analyzedImages.length, 2);
   assert.deepEqual(analyzedImages.map((item) => item.rawUrl), imageUrls);
-  assert.deepEqual(result?.userMessage?.metadata?.imageUrls, [
+  assert.equal(result?.userMessage?.metadata?.imageUrls, undefined);
+  assert.deepEqual(result?.userMessage?.metadata?.archivedImageUrls, [
     '/MindSpace/user-1/public/wechat-mp/first.jpg',
     '/MindSpace/user-1/public/wechat-mp/second.jpg',
   ]);
   assert.match(result?.userMessage?.content?.[0]?.text ?? '', /本轮用户仅上传 2 张图片/);
   assert.match(result?.userMessage?.content?.[0]?.text ?? '', /图片2/);
+  assert.doesNotMatch(result?.userMessage?.content?.[0]?.text ?? '', /\[图片\d+\]:/);
 });
 
 test('buildVisionPayload does not mark billable usage when vision analysis fails', async () => {
@@ -171,4 +173,9 @@ test('buildVisionPayload strips image_url content parts for text-only Goose prov
     false,
   );
   assert.match(result?.userMessage?.content?.[0]?.text ?? '', /蓝色方块/);
+  assert.equal(result?.userMessage?.metadata?.imageUrls, undefined);
+  assert.deepEqual(result?.userMessage?.metadata?.archivedImageUrls, [
+    '/api/mindspace/v1/assets/asset-7/download?inline=1',
+  ]);
+  assert.doesNotMatch(result?.userMessage?.content?.[0]?.text ?? '', /\[图片\d+\]:/);
 });