Remove unused variables from memory performance test

Removed beforeClear and afterClear variables that were not being used.
The test now simply verifies that storage.clear() properly resets the
storage stats, which is the actual intent of the test.

Author: claude

tests/performance/logPerformance.test.ts

@@ -320,18 +320,14 @@ describe('Log Performance Tests', () => {
         storage.storeLog(`cmd${i}`, 'bash', '/', generateLargeOutput(1000), '', 0);
       }
 
-      const beforeClear = process.memoryUsage().heapUsed;
       storage.clear();
 
       // Force garbage collection if available
       if (global.gc) {
         global.gc();
       }
 
-      // Give some time for GC
-      const afterClear = process.memoryUsage().heapUsed;
-
-      // Storage should be empty
+      // Storage should be empty after clear
       expect(storage.getStats().totalLogs).toBe(0);
       expect(storage.getStats().totalSize).toBe(0);
     });