docs(changelog): release v0.6.0 and bump package version

Update version from 0.5.0 to 0.6.0 in package.json, set v0.6.0
release date, and update badge statuses (v0.6.0 → Latest, v0.5.0 → Previous).

src/pages/changelog.astro

@@ -23,13 +23,13 @@ import BaseLayout from '../layouts/BaseLayout.astro';
     <!-- v0.6.0 Section -->
     <section id="v0-6-0" class="changelog-section">
       <div class="container">
-        <div class="version-card version-development">
+        <div class="version-card version-latest">
           <div class="version-header">
             <div class="version-info">
                <h2 class="version-number">v0.6.0</h2>
-              <span class="version-date">TBD</span>
+              <span class="version-date">April 9, 2026</span>
             </div>
-            <span class="version-badge badge-development">Development</span>
+            <span class="version-badge badge-latest">Latest</span>
           </div>
           
            <div class="version-content">
@@ -75,13 +75,13 @@ import BaseLayout from '../layouts/BaseLayout.astro';
     <!-- v0.5.0 Section -->
     <section id="v0-5-0" class="changelog-section">
       <div class="container">
-        <div class="version-card version-latest">
+        <div class="version-card version-previous">
           <div class="version-header">
             <div class="version-info">
                <h2 class="version-number">v0.5.0</h2>
               <span class="version-date">March 25, 2026</span>
             </div>
-            <span class="version-badge badge-latest">Latest</span>
+            <span class="version-badge badge-previous">Previous</span>
           </div>
           
            <div class="version-content">