FIX: omit thinking tokens from chat

lib/ai_bot/playground.rb

@@ -335,9 +335,9 @@ def reply_to_chat_message(message, channel, context_post_ids)
         in_reply_to_id = channel.direct_message_channel? ? message.id : nil
 
         new_prompts =
-          bot.reply(context) do |partial, cancel, placeholder|
+          bot.reply(context) do |partial, cancel, placeholder, type|
             # no support for tools or thinking by design
-            next if !partial.is_a?(String)
+            next if type == :thinking || type == :tool_details || type == :partial_tool
             if !reply
               # just eat all leading spaces we can not create the message
               next if partial.blank?

spec/lib/modules/ai_bot/playground_spec.rb

@@ -397,14 +397,21 @@
           guardian: guardian,
         )
 
+        thinking_partial =
+          DiscourseAi::Completions::Thinking.new(
+            message: "I should say hello",
+            signature: "thinking-signature-123",
+            partial: true,
+          )
+
         thinking =
           DiscourseAi::Completions::Thinking.new(
             message: "I should say hello",
             signature: "thinking-signature-123",
             partial: false,
           )
         DiscourseAi::Completions::Llm.with_prepared_responses(
-          [[thinking, thinking, "wo", "rld", thinking]],
+          [[thinking_partial, thinking, "wo", "rld"]],
         ) do |_, _, _prompts|
           ChatSDK::Message.create(
             channel_id: channel.id,