Add centralized API client with axios interceptors, remove vue-axios

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

tests/stores/performance.test.js

@@ -5,18 +5,19 @@ vi.mock('@/module/apiError.js', () => ({
   default: vi.fn(),
 }));
 
+const { mockGet } = vi.hoisted(() => ({ mockGet: vi.fn() }));
+vi.mock('@/api/client.js', () => ({
+  default: { get: mockGet },
+}));
+
 import usePerformanceStore from '@/stores/performance.js';
 
 describe('performanceStore', () => {
   let store;
-  const mockAxios = {
-    get: vi.fn(),
-  };
 
   beforeEach(() => {
     setActivePinia(createPinia());
     store = usePerformanceStore();
-    store.$axios = mockAxios;
     vi.clearAllMocks();
   });
 
@@ -33,28 +34,28 @@ describe('performanceStore', () => {
   describe('getPerformance', () => {
     it('fetches log performance data', async () => {
       const mockData = { time: { charts: [] }, freq: { charts: [] } };
-      mockAxios.get.mockResolvedValue({ data: mockData });
+      mockGet.mockResolvedValue({ data: mockData });
 
       await store.getPerformance('log', 1);
 
-      expect(mockAxios.get).toHaveBeenCalledWith(
+      expect(mockGet).toHaveBeenCalledWith(
         '/api/logs/1/performance',
       );
       expect(store.allPerformanceData).toEqual(mockData);
     });
 
     it('fetches filter performance data', async () => {
-      mockAxios.get.mockResolvedValue({ data: { time: {} } });
+      mockGet.mockResolvedValue({ data: { time: {} } });
 
       await store.getPerformance('filter', 5);
 
-      expect(mockAxios.get).toHaveBeenCalledWith(
+      expect(mockGet).toHaveBeenCalledWith(
         '/api/filters/5/performance',
       );
     });
 
     it('does not throw on API failure', async () => {
-      mockAxios.get.mockRejectedValue(new Error('Network error'));
+      mockGet.mockRejectedValue(new Error('Network error'));
 
       // Should not throw - apiError handles it
       await expect(store.getPerformance('log', 1))