Fix BASE_PATH configuration breaking login in development mode

- Normalize BASE_PATH by removing trailing slashes in backend config
- Update Vite dev server proxy to dynamically support BASE_PATH from env
- Add integration tests for BASE_PATH functionality
- All tests pass, build successful

Co-authored-by: samanhappy <2755122+samanhappy@users.noreply.github.com>

tests/integration/base-path-routes.test.ts

@@ -0,0 +1,131 @@
+import { beforeEach, describe, expect, it, jest } from '@jest/globals';
+import request from 'supertest';
+
+// Mock dependencies
+jest.mock('../../src/utils/i18n.js', () => ({
+  __esModule: true,
+  initI18n: jest.fn().mockResolvedValue(undefined),
+}));
+
+jest.mock('../../src/models/User.js', () => ({
+  __esModule: true,
+  initializeDefaultUser: jest.fn().mockResolvedValue(undefined),
+}));
+
+jest.mock('../../src/services/oauthService.js', () => ({
+  __esModule: true,
+  initOAuthProvider: jest.fn(),
+  getOAuthRouter: jest.fn(() => null),
+}));
+
+jest.mock('../../src/services/mcpService.js', () => ({
+  __esModule: true,
+  initUpstreamServers: jest.fn().mockResolvedValue(undefined),
+  connected: jest.fn().mockReturnValue(true),
+}));
+
+jest.mock('../../src/middlewares/userContext.js', () => ({
+  __esModule: true,
+  userContextMiddleware: jest.fn((_req, _res, next) => next()),
+  sseUserContextMiddleware: jest.fn((_req, _res, next) => next()),
+}));
+
+describe('AppServer with BASE_PATH configuration', () => {
+  // Save original BASE_PATH
+  const originalBasePath = process.env.BASE_PATH;
+  
+  beforeEach(() => {
+    jest.clearAllMocks();
+    // Clear module cache to allow fresh imports with different config
+    jest.resetModules();
+  });
+  
+  afterEach(() => {
+    // Restore original BASE_PATH or remove it
+    if (originalBasePath !== undefined) {
+      process.env.BASE_PATH = originalBasePath;
+    } else {
+      delete process.env.BASE_PATH;
+    }
+  });
+
+  const flushPromises = async () => {
+    await new Promise((resolve) => setImmediate(resolve));
+  };
+
+  it('should serve auth routes with BASE_PATH=/mcphub/', async () => {
+    // Set environment variable for BASE_PATH (with trailing slash)
+    process.env.BASE_PATH = '/mcphub/';
+    
+    // Dynamically import after setting env var
+    const { AppServer } = await import('../../src/server.js');
+    const config = await import('../../src/config/index.js');
+    
+    // Verify config loaded the BASE_PATH and normalized it (removed trailing slash)
+    expect(config.default.basePath).toBe('/mcphub');
+    
+    const appServer = new AppServer();
+    await appServer.initialize();
+    await flushPromises();
+    
+    const app = appServer.getApp();
+    
+    // Test that /mcphub/config endpoint exists
+    const configResponse = await request(app).get('/mcphub/config');
+    expect(configResponse.status).not.toBe(404);
+    
+    // Test that /mcphub/public-config endpoint exists
+    const publicConfigResponse = await request(app).get('/mcphub/public-config');
+    expect(publicConfigResponse.status).not.toBe(404);
+    
+    // Clean up
+    delete process.env.BASE_PATH;
+  });
+
+  it('should serve auth routes without BASE_PATH (default)', async () => {
+    // Ensure BASE_PATH is not set
+    delete process.env.BASE_PATH;
+    
+    // Dynamically import after clearing env var
+    jest.resetModules();
+    const { AppServer } = await import('../../src/server.js');
+    const config = await import('../../src/config/index.js');
+    
+    // Verify config has empty BASE_PATH
+    expect(config.default.basePath).toBe('');
+    
+    const appServer = new AppServer();
+    await appServer.initialize();
+    await flushPromises();
+    
+    const app = appServer.getApp();
+    
+    // Test that /config endpoint exists (without base path)
+    const configResponse = await request(app).get('/config');
+    expect(configResponse.status).not.toBe(404);
+    
+    // Test that /public-config endpoint exists
+    const publicConfigResponse = await request(app).get('/public-config');
+    expect(publicConfigResponse.status).not.toBe(404);
+  });
+
+  it('should correctly mount API routes with BASE_PATH', async () => {
+    process.env.BASE_PATH = '/test-base/';
+    
+    jest.resetModules();
+    const { AppServer } = await import('../../src/server.js');
+    
+    const appServer = new AppServer();
+    await appServer.initialize();
+    await flushPromises();
+    
+    const app = appServer.getApp();
+    
+    // Test that API routes are accessible with base path
+    const apiHealthResponse = await request(app).get('/health');
+    expect(apiHealthResponse.status).not.toBe(404);
+    
+    // Clean up
+    delete process.env.BASE_PATH;
+  });
+});