Fix double /api/ prefix in API endpoint calls

When VITE_API_URL=/api, axios baseURL is already set to /api. However, all endpoint calls included the /api/ prefix, creating double paths like /api/api/auth/login/.

Removed /api/ prefix from 81 API endpoint calls across 22 files:
- src/api/auth.ts - Fixed login, logout, me, refresh, hijack endpoints
- src/api/client.ts - Fixed token refresh endpoint
- src/api/profile.ts - Fixed all profile, email, password, MFA, sessions endpoints
- src/hooks/*.ts - Fixed all remaining API calls (users, appointments, resources, etc)
- src/pages/*.tsx - Fixed signup and email verification endpoints

This ensures API requests use the correct path: /api/auth/login/ instead of /api/api/auth/login/

🤖 Generated with Claude Code

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

frontend/src/api/client.ts

@@ -71,7 +71,7 @@ apiClient.interceptors.response.use(
         // Try to refresh token (from cookie)
         const refreshToken = getCookie('refresh_token');
         if (refreshToken) {
-          const response = await axios.post(`${API_BASE_URL}/api/auth/refresh/`, {
+          const response = await axios.post(`${API_BASE_URL}/auth/refresh/`, {
             refresh: refreshToken,
           });