chore: use ruff to lint and auto-format

backend/src/agents/lead_agent/agent.py

@@ -1,4 +1,5 @@
 from langchain.agents import create_agent
+
 from src.agents.lead_agent.prompt import apply_prompt_template
 from src.models import create_chat_model
 from src.tools import get_available_tools

backend/src/agents/lead_agent/prompt.py

@@ -71,7 +71,4 @@ All temporary work happens in `{MOUNT_POINT}/user-data/workspace`. Final deliver
 
 
 def apply_prompt_template() -> str:
-    return (
-        SYSTEM_PROMPT
-        + f"\n<current_date>{datetime.now().strftime("%Y-%m-%d, %A")}</current_date>"
-    )
+    return SYSTEM_PROMPT + f"\n<current_date>{datetime.now().strftime('%Y-%m-%d, %A')}</current_date>"