Convert all store files from JavaScript to TypeScript

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

tests/stores/acctMgmt.test.js

@@ -13,7 +13,7 @@ vi.mock('@/api/client.js', () => ({
 }));
 
 // Mock login store to avoid its side effects
-vi.mock('@/stores/login.ts', () => {
+vi.mock('@/stores/login', () => {
   const { defineStore } = require('pinia');
   return {
     useLoginStore: defineStore('loginStore', {
@@ -27,7 +27,7 @@ vi.mock('@/stores/login.ts', () => {
   };
 });
 
-import { useAcctMgmtStore } from '@/stores/acctMgmt.ts';
+import { useAcctMgmtStore } from '@/stores/acctMgmt';
 
 describe('acctMgmtStore', () => {
   let store;