Fix footer copyright HTML rendering in all layouts

The columns, minimal, and stacked footer layouts were rendering
the copyright string as raw text instead of HTML, causing the
'Designed by Hans Martens' link to appear as code on the page.

Changed all three layouts to use set:html consistent with the
simple layout which was already rendering correctly.

https://claude.ai/code/session_019mp7rTrQPx9yxp17hgjsYb

src/components/layout/Footer.astro

@@ -274,9 +274,7 @@ function getSocialIcon(platform: string): string {
             ) : (
               <>
                 {showCopyright && (
-                  <p class="text-sm text-foreground-muted">
+                  <p class="text-sm text-foreground-muted" set:html={processedCopyright} />
-                    {processedCopyright}
-                  </p>
                 )}
                 {legalLinks.length > 0 && (
                   <div class="flex items-center gap-[var(--space-inline-lg)]">
@@ -300,9 +298,7 @@ function getSocialIcon(platform: string): string {
     {layout === 'minimal' && (
       <div class="text-center">
         {showCopyright && (
-          <p class="text-sm text-foreground-muted">
+          <p class="text-sm text-foreground-muted" set:html={processedCopyright} />
-            {processedCopyright}
-          </p>
         )}
       </div>
     )}
@@ -365,9 +361,7 @@ function getSocialIcon(platform: string): string {
         {(showCopyright || legalLinks.length > 0) && (
           <div class="pt-[var(--space-stack-lg)] border-t border-border w-full flex flex-col items-center gap-[var(--space-stack-md)]">
             {showCopyright && (
-              <p class="text-sm text-foreground-muted">
+              <p class="text-sm text-foreground-muted" set:html={processedCopyright} />
-                {processedCopyright}
-              </p>
             )}
             {legalLinks.length > 0 && (
               <div class="flex items-center gap-[var(--space-inline-lg)]">