fix: resolve all ruff lint errors (F401, F841, E741, I001)

Remove unused imports, fix unsorted import blocks, rename ambiguous
variable, and remove unused local variable assignment.

tests/conformance/benchmark_parallel.py

@@ -12,16 +12,16 @@ Usage:
 
 from __future__ import annotations
 
-import asyncio
-import json
 import os
-import statistics
 import sys
-import tempfile
+import json
 import time
-from dataclasses import dataclass, field
-from pathlib import Path
+import asyncio
+import tempfile
+import statistics
 from typing import Any
+from pathlib import Path
+from dataclasses import field, dataclass
 
 HANZO_ROOT = Path(os.environ.get("HANZO_ROOT", Path.home() / "work" / "hanzo"))
 TIMEOUT = 30

tests/conformance/run_conformance.py

@@ -25,17 +25,17 @@ Usage:
 
 from __future__ import annotations
 
-import asyncio
-import json
 import os
 import re
-import shutil
 import sys
-import tempfile
+import json
 import time
-from dataclasses import dataclass, field
-from pathlib import Path
+import shutil
+import asyncio
+import tempfile
 from typing import Any
+from pathlib import Path
+from dataclasses import field, dataclass
 
 # ── Configuration ─────────────────────────────────────────────────────────────