chore: Change trial period from 30-day to 14-day

Updated all trial period references:
- '30-day free trial' → '14-day free trial'
- '30 day' → '14 day'

Applied to:
- reserve-study-software.html
- investment-management.html
- special-assessment-calculator.html

reserve-study-software.html

@@ -51,7 +51,7 @@
                 <a href="#comparison" class="btn btn-ghost btn-lg">See Comparison →</a>
             </div>
             <div class="hero-trust">
-                <p>✓ No credit card required &nbsp; ✓ 30-day free trial &nbsp; ✓ Cancel anytime</p>
+                <p>✓ No credit card required &nbsp; ✓ 14-day free trial &nbsp; ✓ Cancel anytime</p>
             </div>
         </div>
     </section>