feat(avatar): understand BOXIM image messages

digital-avatar-app/backend/tests/test_chat_images.py

@@ -17,6 +17,7 @@ from routers.chat import (
     _resolve_reply,
 )
 from services.chat_attachment_service import purge_expired_chat_attachments
+from services.token_billing import InsufficientTokensError
 from services.vision_service import PreparedImage
 
 
@@ -75,6 +76,22 @@ def test_non_owner_cannot_upload_chat_image(authorization_context):
     assert response.status_code == 403
 
 
+def test_image_upload_preserves_insufficient_points_response(authorization_context):
+    context = authorization_context
+    with patch(
+        "routers.chat._analyze_image_bytes",
+        side_effect=InsufficientTokensError("积分余额不足"),
+    ):
+        response = client.post(
+            f"/api/avatar/{context['avatar'].id}/chat/images",
+            headers=context["owner_headers"],
+            files={"file": ("private.png", b"image-bytes", "image/png")},
+        )
+
+    assert response.status_code == 402
+    assert response.json()["detail"] == "积分余额不足"
+
+
 def test_public_share_can_upload_without_exposing_analysis_details(authorization_context):
     context = authorization_context
     db = SessionLocal()