fix(openrouter): list image generation in the packaged endpoint matrix

The proxy's public endpoint listing reads
litellm/provider_endpoints_support_backup.json, where openrouter
image_generations was still false while provider_endpoints_support.json now
marks it true. Only that value changes, since the two files already differ
elsewhere on main

litellm/provider_endpoints_support_backup.json

@@ -1810,7 +1810,7 @@
         "messages": true,
         "responses": true,
         "embeddings": true,
-        "image_generations": false,
+        "image_generations": true,
         "audio_transcriptions": false,
         "audio_speech": false,
         "moderations": false,

tests/unit/llms/openrouter/image_generation/test_openrouter_image_gen_transformation.py

@@ -1,4 +1,5 @@
 import json
+from pathlib import Path
 from typing import Final
 from unittest.mock import MagicMock, patch
 
@@ -534,3 +535,18 @@ def test_openrouter_error_response_surfaces_as_not_found_error():
             api_key="sk-test",
             client=_client(recorder),
         )
+
+
+@pytest.mark.parametrize(
+    "matrix_path",
+    [
+        Path(litellm.__file__).parent.parent / "provider_endpoints_support.json",
+        Path(litellm.__file__).parent / "provider_endpoints_support_backup.json",
+    ],
+    ids=["root", "backup"],
+)
+def test_endpoint_matrix_lists_openrouter_image_generations(matrix_path: Path):
+    """The proxy's public endpoint listing reads the backup copy shipped inside the package"""
+    matrix = json.loads(matrix_path.read_text())
+
+    assert matrix["providers"]["openrouter"]["endpoints"]["image_generations"] is True