feat(sidebar): add sidebar expand button

Added a button to expand the sidebar to the sidebar and reorganized
sidebar elements accordingly.

src/features/sidebar/components/Sidebar.vue

@@ -14,15 +14,37 @@ See the License for the specific language governing permissions and
 limitations under the License.
 -->
 
+<script setup>
+import SidebarExpandButton from './SidebarExpandButton.vue';
+</script>
+
 <template>
     <nav class="sidebar">
+        <div class="sidebar-controls">
+            <SidebarExpandButton />
+        </div>
+        <div class="sidebar-content">
             <slot />
+        </div>
     </nav>
 </template>
 
 <style scoped>
 .sidebar {
     border-right: 1px solid var(--border);
+}
+
+.sidebar-controls {
+    display: flex;
+    align-items: center;
+    justify-content: end;
+    padding: 1em 20px;
+    padding-bottom: 0;
+    margin-bottom: 8px;
+}
+
+.sidebar-content {
     padding: 20px;
+    padding-top: 0;
 }
 </style>

src/features/sidebar/components/SidebarExpandButton.vue

@@ -0,0 +1,41 @@
+<!--
+Copyright 2026 Seekra
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+-->
+
+<script setup>
+import Icon from '@/features/icons/components/Icon.vue';
+
+const emit = defineEmits(['click']);
+
+const click = function click (event) {
+    emit('click', event);
+};
+</script>
+
+<template>
+    <button class="button sidebar-expand-button">
+        <Icon name="sidebar-expand" @click="click" />
+    </button>
+</template>
+
+<style scoped>
+.sidebar-expand-button {
+    display: flex;
+    justify-content: center;
+    align-items: center;
+    padding: 4px;
+    border-radius: 10px;
+}
+</style>