style(memory): apply ruff formatting and linting fixes

Auto-fixed linting errors and formatting issues:
- Removed unused imports (F401): pytest, Any, AnalysisType, MemoryType, OutcomeType
- Removed unused variable (F841): hooks variable in test
- Applied consistent formatting across memory service and test files

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

backend/tests/unit/services/memory/integration/test_lifecycle.py

@@ -105,6 +105,7 @@ class TestLifecycleHooks:
 
     def test_register_spawn_hook(self, lifecycle_hooks: LifecycleHooks) -> None:
         """Should register spawn hook."""
+
         async def my_hook(event: LifecycleEvent) -> None:
             pass
 
@@ -115,7 +116,7 @@ class TestLifecycleHooks:
 
     def test_register_all_hooks(self, lifecycle_hooks: LifecycleHooks) -> None:
         """Should register hooks for all event types."""
-        hooks = [
+        [
             lifecycle_hooks.on_spawn(AsyncMock()),
             lifecycle_hooks.on_pause(AsyncMock()),
             lifecycle_hooks.on_resume(AsyncMock()),