fix: resolve all ruff lint errors across codebase

Auto-fixed whitespace, import sorting, and unused imports.
Added noqa directives for intentional patterns (try-except-pass
in cleanup code, conditional imports for availability checks).
Updated ruff per-file-ignores for benchmark/test/example files.

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

Author: HimashaHerath

benchmark/__init__.py

@@ -11,4 +11,4 @@
 __all__ = [
     'EvaluationFramework',
     'ReasoningTestGenerator'
-] 
+]