Fix some ruff issues in code

agent/agent.py

@@ -2,7 +2,8 @@
 
 import json
 import logging
-from typing import Any, AsyncGenerator
+from collections.abc import AsyncGenerator
+from typing import Any
 
 from infrastructure.persistence import get_memory
 
@@ -77,7 +78,7 @@ class Agent:
         tools_spec = self.prompt_builder.build_tools_spec()
 
         # Tool execution loop
-        for iteration in range(self.max_tool_iterations):
+        for _iteration in range(self.max_tool_iterations):
             # Call LLM with tools
             llm_result = self.llm.complete(messages, tools=tools_spec)
 
@@ -229,7 +230,7 @@ class Agent:
         tools_spec = self.prompt_builder.build_tools_spec()
 
         # Tool execution loop
-        for iteration in range(self.max_tool_iterations):
+        for _iteration in range(self.max_tool_iterations):
             # Call LLM with tools
             llm_result = self.llm.complete(messages, tools=tools_spec)
 
@@ -317,7 +318,9 @@ class Agent:
                 )
 
                 # Stream tool result as content
-                result_text = f"\n🔧 {tool_name}: {json.dumps(tool_result, ensure_ascii=False)}\n"
+                result_text = (
+                    f"\n🔧 {tool_name}: {json.dumps(tool_result, ensure_ascii=False)}\n"
+                )
                 yield {
                     "id": completion_id,
                     "object": "chat.completion.chunk",