Update user profile

Update the current user's profile information. All fields are optional - only provided fields will be updated. **Authentication Required:** Yes - Valid JWT token in Authorization header **User Identification:** The system supports finding users by ID, email, or phone number from the authentication token. **Available Fields:** - **firstName** (string, 1-50 chars): User's first name - **lastName** (string, 1-50 chars): User's last name - **gender** (enum): MALE, FEMALE, OTHER - **birthday** (ISO 8601 date-time): User's birthday - **nationality** (2-char ISO code): Country code (e.g., US, DE, FR) - **homeBase** (string, 1-100 chars): User's home location - **language** (enum): DE, EN, AR - **appearance** (enum): AUTO, LIGHT, DARK - **termsAccepted** (boolean): Flag indicating user accepted terms of conditions. When set to true, automatically sets termsAcceptedAt timestamp - **marketingAccepted** (boolean): Flag indicating user accepted marketing communications. When set to true, automatically sets marketingAcceptedAt timestamp **Usage:** 1. Generate a test token using the `/auth/generate-test-token` endpoint 2. Include the token in the Authorization header: `Bearer <token>` 3. Send a PATCH request with the fields you want to update 4. Only provided fields will be updated; others remain unchanged **Validation Rules:** - firstName/lastName: 1-50 characters - nationality: Exactly 2 characters (ISO Alpha-2) - homeBase: 1-100 characters - birthday: Valid ISO 8601 date-time format - At least one field must be provided **Note:** This endpoint requires a valid JWT token. The system will automatically find the user by ID, email, or phone number from the token.