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/memory/cache/cache_manager.py

@@ -50,7 +50,9 @@ class CacheStats:
             "embedding_cache": self.embedding_cache,
             "retrieval_cache": self.retrieval_cache,
             "overall_hit_rate": self.overall_hit_rate,
-            "last_cleanup": self.last_cleanup.isoformat() if self.last_cleanup else None,
+            "last_cleanup": self.last_cleanup.isoformat()
+            if self.last_cleanup
+            else None,
             "cleanup_count": self.cleanup_count,
         }
 
@@ -104,7 +106,8 @@ class CacheManager:
         else:
             self._embedding_cache = create_embedding_cache(
                 max_size=self._settings.cache_max_items,
-                default_ttl_seconds=self._settings.cache_ttl_seconds * 12,  # 1hr for embeddings
+                default_ttl_seconds=self._settings.cache_ttl_seconds
+                * 12,  # 1hr for embeddings
                 redis=redis,
             )
 
@@ -271,7 +274,9 @@ class CacheManager:
 
         # Invalidate retrieval cache
         if self._retrieval_cache:
-            uuid_id = UUID(str(memory_id)) if not isinstance(memory_id, UUID) else memory_id
+            uuid_id = (
+                UUID(str(memory_id)) if not isinstance(memory_id, UUID) else memory_id
+            )
             count += self._retrieval_cache.invalidate_by_memory(uuid_id)
 
         logger.debug(f"Invalidated {count} cache entries for {memory_type}:{memory_id}")