fix: resolve ruff lint errors (import sorting, unused imports)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: kmad

rlm/environments/docker_repl.py

@@ -16,7 +16,6 @@
 import threading
 import time
 from http.server import BaseHTTPRequestHandler, HTTPServer
-from typing import Any
 
 from rlm.core.comms_utils import LMRequest, send_lm_request, send_lm_request_batched
 from rlm.core.types import ContextPayload, REPLResult, RLMChatCompletion

rlm/environments/modal_repl.py

@@ -3,7 +3,6 @@
 import textwrap
 import threading
 import time
-from typing import Any
 
 import modal
 import requests

tests/test_dataframe_utils.py

@@ -14,7 +14,6 @@
     is_pandas_dataframe,
 )
 
-
 # ---------------------------------------------------------------------------
 # Detection helpers
 # ---------------------------------------------------------------------------