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/app/services/context/budget/allocator.py

@@ -344,7 +344,12 @@ class BudgetAllocator:
             Rebalanced budget
         """
         if prioritize is None:
-            prioritize = [ContextType.KNOWLEDGE, ContextType.MEMORY, ContextType.TASK, ContextType.SYSTEM]
+            prioritize = [
+                ContextType.KNOWLEDGE,
+                ContextType.MEMORY,
+                ContextType.TASK,
+                ContextType.SYSTEM,
+            ]
 
         # Calculate unused tokens per type
         unused: dict[str, int] = {}