fix: remove APC primer from history, scope preserve_thinking to tool-call turns

chat_template.jinja

@@ -226,14 +226,12 @@
     {%- set continue_same_model_turn = (role == 'model' and ns.prev_non_tool_role == 'assistant') -%}
     {%- if not continue_same_model_turn -%}
         {{- '<|turn>' + role + '\n' }}
-        {%- if role == 'model' and not enable_thinking and not (message.get('reasoning') or message.get('reasoning_content')) -%}
-            {{- '<|channel>thought\n<channel|>' -}}
-        {%- endif -%}
+
     {%- endif -%}
 
     {#- Render reasoning/reasoning_content as thinking channel -#}
     {%- set thinking_text = message.get('reasoning') or message.get('reasoning_content') -%}
-    {%- set thinking_gate = (loop.index0 > ns_turn.last_user_idx) or preserve_thinking -%}
+    {%- set thinking_gate = (loop.index0 > ns_turn.last_user_idx) or (preserve_thinking and message.get('tool_calls')) -%}
     {%- if thinking_text and thinking_gate -%}
         {{- '<|channel>thought\n' + thinking_text + '\n<channel|>' -}}
     {%- endif -%}