debug: log whether AutoAgents passes json_schema to chat method

Added logging to verify if AutoAgents ReAct framework actually uses
the output_schema() method and passes it to chat() calls.

Will show:
- ✅ AutoAgents passed json_schema - API-level enforcement active
- ⚠️  AutoAgents did NOT pass json_schema - prompt-only enforcement

This answers whether structured outputs are enforced at API level
or only through prompt instructions.

Author: jruokola

crates/codegraph-mcp/src/autoagents/agent_builder.rs

@@ -72,6 +72,13 @@ impl ChatProvider for CodeGraphChatAdapter {
         _tools: Option<&[Tool]>,
         json_schema: Option<autoagents::llm::chat::StructuredOutputFormat>,
     ) -> Result<Box<dyn ChatResponse>, LLMError> {
+        // Log whether schema is being passed by AutoAgents
+        if json_schema.is_some() {
+            tracing::info!("✅ AutoAgents passed json_schema to chat()");
+        } else {
+            tracing::warn!("⚠️  AutoAgents did NOT pass json_schema - schema enforcement may be prompt-only!");
+        }
+
         // Convert AutoAgents messages to CodeGraph messages
         let cg_messages: Vec<Message> = messages
             .iter()