feat: replace all booking CTAs with BookedIn scheduling link

Replace /contact/ booking links sitewide with the BookedIn external
scheduling URL (https://bookedin.com/book/lahr-carpet-cleaning-and-upholstery).
All "Book Now" and "Get a Free Estimate" buttons across 38 HTML pages now
open the BookedIn scheduler in a new tab. Added a "Book Online" CTA button
to the shared nav bar and a booking link in the footer (components.js).
The contact page retains its form as a secondary option, with a prominent
"Book Online Instantly" banner added above it.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

services/add-ons/index.html

@@ -20,7 +20,7 @@
                 <span class="hero-eyebrow"><i class="fas fa-map-marker-alt"></i> Waterloo, Seneca Falls &amp; the Finger Lakes</span>
                 <h1>Carpet Cleaning Add-On Services</h1>
                 <p>Standard cleaning handles most situations. Some homes need more. These optional treatments are available at booking and extend the results of your service.</p>
-                <a href="/contact/" class="btn btn-primary btn-large">Book Now</a>
+                <a href="https://bookedin.com/book/lahr-carpet-cleaning-and-upholstery" target="_blank" rel="noopener noreferrer" class="btn btn-primary btn-large">Book Now</a>
             </div>
         </div>
     </section>
@@ -65,7 +65,7 @@
                     <h2>Tell Us What You Are Dealing With When You Book</h2>
                     <p>When you contact us to schedule, describe the specific problems you want addressed. Pet odors, heavy soiling, or a request for protector are all things we factor into the job before arriving. Nothing is added without your knowledge.</p>
                     <p>These treatments are optional. Not every home needs them. We will tell you honestly at the time of booking whether an add-on makes sense for your situation.</p>
-                    <a href="/contact/" class="btn btn-primary">Book Now</a>
+                    <a href="https://bookedin.com/book/lahr-carpet-cleaning-and-upholstery" target="_blank" rel="noopener noreferrer" class="btn btn-primary">Book Now</a>
                 </div>
                 <div class="why-choose-image" style="background-image: url('/assets/images/hero/hero-add-ons.webp')"></div>
             </div>
@@ -78,7 +78,7 @@
                 <h2>Get the Full Treatment Your Home Needs</h2>
                 <p>Serving Waterloo, Seneca Falls, and the Finger Lakes region.</p>
                 <div class="cta-actions">
-                    <a href="/contact/" class="btn btn-primary btn-large">Book Now</a>
+                    <a href="https://bookedin.com/book/lahr-carpet-cleaning-and-upholstery" target="_blank" rel="noopener noreferrer" class="btn btn-primary btn-large">Book Now</a>
                     <a href="tel:315-719-1218" class="btn btn-ghost btn-large"><i class="fas fa-phone"></i> 315-719-1218</a>
                 </div>
             </div>