feat: add clear state functionality in footer

Introduced a "Delete all entries" link in the footer that clears
local storage state upon confirmation from the user. Modified
CSS to properly align new footer elements. This improvement
enhances user control over stored data, ensuring an easy way
to reset the application state.

example.css

@@ -40,4 +40,14 @@ footer {
 
 footer a {
     color: white;
+}
+
+.footer-left {
+    float: left;
+    margin-left: 1em;
+}
+
+.footer-right {
+    float: right;
+    margin-right: 1em;
 }

example.html

@@ -22,7 +22,8 @@
         </section>
     </main>
     <footer>
-        <p>Brought to you by <a href="https://git.private.coffee/kumi/kanblendar">Kumi</a></p>
+        <div class="footer-left"><a href="#" onclick="javascript:clearState(); return false;">Delete all entries</a></div>
+        <div class="footer-right">Brought to you by <a href="https://git.private.coffee/kumi/kanblendar">Kumi</a></div>
     </footer>
 
     <!-- Optional: Developers can define their own modal here -->

example.js

@@ -17,4 +17,14 @@ document.addEventListener('DOMContentLoaded', () => {
         console.log('State loaded on page load!');
     }
 
-});
+});
+
+function clearState() {
+    if (!confirm('Are you sure you want to clear the state?')) {
+        return;
+    }
+    
+    localStorage.removeItem('kanblendarState');
+    console.log('State cleared!');
+    document.location.reload();
+}