chore: Update version references from v1.5 to v1.6

Update all version references to v1.6:
- index.html: Promo banner updated from v1.5 to v1.6
- index.html: Release notes link updated from v15-release to v16-release
- index.html: Promo text updated with v1.6 features
- _includes/footer.html: Footer version updated from v1.5 to v1.6
- _includes/footer.html: Default version updated from 1.5.0 to 1.6.0

This ensures all website pages consistently reference v1.6 as the current version.

Author: xaviercallens

_includes/footer.html

@@ -4,7 +4,7 @@
       <div class="footer-section">
         <div class="footer-brand">
           <img src="{{ '/assets/images/AMCPLogo.png' | relative_url }}" alt="AMCP Logo" class="footer-logo">
-          <h3>AMCP v1.5</h3>
+          <h3>AMCP v1.6</h3>
           <p>Enterprise-grade multi-agent communication framework for modern distributed systems.</p>
         </div>
         <div class="footer-social">
@@ -74,7 +74,7 @@ <h4>Resources</h4>
           <p>&copy; {{ 'now' | date: "%Y" }} AMCP Development Team. Released under the MIT License.</p>
         </div>
         <div class="footer-meta">
-          <span class="footer-version">Version {{ site.version | default: "1.5.0" }}</span>
+          <span class="footer-version">Version {{ site.version | default: "1.6.0" }}</span>
           <span class="footer-separator">•</span>
           <a href="{{ '/privacy/' | relative_url }}">Privacy Policy</a>
           <span class="footer-separator">•</span>

index.html

@@ -16,11 +16,11 @@ <h1>Agentic Framework - Agent Mesh Communication Protocol</h1>
   <div class="container">
     <div class="promo-content">
       <div class="promo-text">
-        <h2>🚀 AMCP v1.5 Released</h2>
-        <p>Enhanced Agent Mobility • Native LLM Integration • Zero-Trust Security</p>
+        <h2>🚀 AMCP v1.6 Released</h2>
+        <p>Advanced Agent Orchestration • Enterprise Security • Multi-Cloud Deployment</p>
       </div>
       <div class="promo-actions">
-        <a href="/docs/blog/v15-release.html" class="btn btn-promo">Release Notes</a>
+        <a href="/docs/blog/v16-release.html" class="btn btn-promo">Release Notes</a>
         <a href="/blog/" class="btn btn-promo-outline">Read Blog</a>
       </div>
     </div>