Broaden client-neutral OpenAI and llama.cpp chat compatibility

endpoint.py

@@ -169,7 +169,9 @@ class APIHandler(BaseHTTPRequestHandler):
     def log_message(self,*args):pass
     def compatibility_headers(self):
         info=getattr(self,'compatibility',{})
-        if info:
+        if info.get('ignored'):
+            self.send_header('X-Athena-Compatibility-Ignored',','.join(info['ignored']))
+        if 'requested' in info:
             self.send_header('X-Athena-Reasoning-Requested',info['requested'])
             self.send_header('X-Athena-Reasoning-Effective',info['effective'])
             self.send_header('X-Athena-Reasoning-Semantics',info['semantics'])
@@ -209,6 +211,9 @@ class APIHandler(BaseHTTPRequestHandler):
                 try:ep.video.relay(self) if callable(getattr(type(ep.video),'relay',None)) else relay(self,video['selected'])
                 except ValueError as exc:raise APIError(str(exc)) from None
                 return
+            if self.command=='GET' and self.path=='/v1/capabilities':
+                from api_compat import capabilities
+                return self.send(capabilities())
             model_routes={'/v1/models':'chat','/v1/images/models':'image','/v1/audio/speech/models':'audio','/v1/audio/transcriptions/models':'stt','/v1/audio/music/models':'music'}
             if self.command=='GET' and self.path in model_routes:return self.send(ep.model_list(model_routes[self.path]))
             if self.command=='GET' and self.path=='/health':return self.send({'status':'ok','service':'athena-deck-api'})