Revert "model : gpt-oss revert removal of user defined tokens"

This reverts commit 6d75412.

Author: aldehir

src/llama-vocab.cpp

@@ -2339,13 +2339,6 @@ void llama_vocab::impl::load(llama_model_loader & ml, const LLM_KV & kv) {
             }
         }
 
-        // @ngxson : quick hack for gpt-oss, always render these tokens
-        for (const auto & t : token_to_id) {
-            if (t.first == "<|channel|>" || t.first == "<|message|>" || t.first == "<|start|>") {
-                id_to_token[t.second].attr = LLAMA_TOKEN_ATTR_USER_DEFINED;
-            }
-        }
-
         // sanity checks
         if (special_eos_id != LLAMA_TOKEN_NULL && special_eog_ids.count(special_eos_id) == 0) {
             special_eog_ids.insert(special_eos_id);