added IMAP, LetsEncrypt, update layout

internal/webui/templates/sidebar_email.html

@@ -1,12 +1,17 @@
 {{define "sidebar_email.html"}}
 <nav class="sidebar bg-dark border-end border-secondary position-fixed h-100" style="width: var(--sidebar-width); z-index: 1000;">
     <div class="d-flex flex-column h-100">
-        <div class="p-3 border-bottom border-secondary">
-            <h5 class="text-white mb-0">
-                <i class="bi bi-server me-2"></i>
-                SMTP Server
-            </h5>
-            <small class="text-muted">Management Console</small>
+        <div class="p-3 border-bottom border-secondary d-flex align-items-start justify-content-between">
+            <div>
+                <h5 class="text-white mb-0">
+                    <i class="bi bi-server me-2"></i>
+                    SMTP Server
+                </h5>
+                <small class="text-muted">Management Console</small>
+            </div>
+            <button id="sidebarPinBtn" class="btn btn-sm btn-outline-secondary" title="Unpin sidebar (auto-hide)" onclick="toggleSidebarPin()">
+                <i class="bi bi-pin-angle-fill" id="sidebarPinIcon"></i>
+            </button>
         </div>
 
         <div class="flex-grow-1 overflow-auto">
@@ -41,6 +46,14 @@
                     </a>
                 </li>
 
+                <li class="nav-item mb-1">
+                    <a href="/pymta-manager/mailboxes" class="nav-link text-white {{if eq (dget . "active") "mailboxes"}}active{{end}}">
+                        <i class="bi bi-inbox me-2"></i>
+                        Mailboxes
+                        <span class="badge bg-secondary ms-auto">{{dget . "mailbox_count"}}</span>
+                    </a>
+                </li>
+
                 <li class="nav-item mb-1">
                     <a href="/pymta-manager/ips" class="nav-link text-white {{if eq (dget . "active") "ips"}}active{{end}}">
                         <i class="bi bi-router me-2"></i>
@@ -57,6 +70,13 @@
                     </a>
                 </li>
 
+                <li class="nav-item mb-1">
+                    <a href="/pymta-manager/letsencrypt" class="nav-link text-white {{if eq (dget . "active") "letsencrypt"}}active{{end}}">
+                        <i class="bi bi-patch-check me-2"></i>
+                        Let's Encrypt
+                    </a>
+                </li>
+
                 <li class="nav-item mb-1">
                     <a href="/pymta-manager/logs" class="nav-link text-white {{if eq (dget . "active") "logs"}}active{{end}}">
                         <i class="bi bi-journal-text me-2"></i>