docs: register synthorai in provider_endpoints_support.json

code-quality fails with 'Found 1 undocumented openai_like providers:
synthorai'. check_provider_folders_documented.py requires every entry in
llms/openai_like/providers.json to have one here.

The endpoint flags come from the catalog's category counts, not from
probing: auth sits on the /v1 prefix so unrouted paths also return 401.
There are no embedding or rerank models, so those stay false.

provider_endpoints_support.json

@@ -488,9 +488,7 @@
         "audio_speech": false,
         "moderations": false,
         "batches": false,
-        "rerank": false,
-        "a2a": false,
-        "interactions": false
+        "rerank": false
       }
     },
     "chutes": {
@@ -2957,22 +2955,6 @@
         "rerank": false
       }
     },
-    "charity_engine": {
-      "display_name": "Charity Engine (`charity_engine`)",
-      "url": "https://docs.litellm.ai/docs/providers/charity_engine",
-      "endpoints": {
-        "chat_completions": true,
-        "messages": true,
-        "responses": true,
-        "embeddings": false,
-        "image_generations": false,
-        "audio_transcriptions": false,
-        "audio_speech": false,
-        "moderations": false,
-        "batches": false,
-        "rerank": false
-      }
-    },
     "empiriolabs": {
       "display_name": "EmpirioLabs (`empiriolabs`)",
       "url": "https://docs.litellm.ai/docs/providers/empiriolabs",
@@ -2989,6 +2971,24 @@
         "rerank": false,
         "a2a": false
       }
+    },
+    "synthorai": {
+      "display_name": "Synthorai (`synthorai`)",
+      "url": "https://docs.litellm.ai/docs/providers/synthorai",
+      "endpoints": {
+        "chat_completions": true,
+        "messages": true,
+        "responses": true,
+        "embeddings": false,
+        "image_generations": true,
+        "audio_transcriptions": true,
+        "audio_speech": true,
+        "moderations": false,
+        "batches": false,
+        "rerank": false,
+        "a2a": false,
+        "interactions": false
+      }
     }
   },
   "endpoints": {