Convert all store files from JavaScript to TypeScript

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

tests/stores/cytoscapeStore.test.js

@@ -1,6 +1,6 @@
 import { describe, it, expect, beforeEach, vi } from 'vitest';
 import { setActivePinia, createPinia } from 'pinia';
-import { useCytoscapeStore } from '@/stores/cytoscapeStore.ts';
+import { useCytoscapeStore } from '@/stores/cytoscapeStore';
 import { SAVE_KEY_NAME } from '@/constants/constants.js';
 
 // Mock localStorage since jsdom's localStorage is limited