fix: expand sidebar visibility to all non-desktop screens (≤992px)

- sidebar.css: change .floating-menu-btn breakpoint from max-width:768px
  to max-width:992px so the button appears on tablets as well
- header.css: move .nav-container hide + .floating-menu-btn show into
  the ≤992px block so desktop nav is hidden and sidebar activates on
  all mobile + tablet viewports (Bootstrap lg breakpoint)
- ≥993px (desktop): header nav visible, sidebar hidden
- ≤992px (tablet + mobile): header nav hidden, sidebar floating button shown"

views/components/header/header.css

@@ -299,6 +299,20 @@
   .banner-container {
     height: 350px;
   }
+
+  /* Hide desktop nav, show sidebar button on tablet */
+  .nav-container {
+    display: none;
+  }
+
+  .header-contact-section {
+    display: none;
+  }
+
+  /* Show floating menu button on tablet */
+  .floating-menu-btn {
+    display: flex;
+  }
 }
 
 @media (max-width: 768px) {
@@ -311,10 +325,6 @@
     margin: 0 10px;
   }
 
-  .nav-container {
-    display: none; /* Hide desktop nav on mobile */
-  }
-
   .mobile-menu-btn {
     display: block;
   }
@@ -329,10 +339,6 @@
     flex-grow: 1;
   }
 
-  .header-contact-section {
-    display: none; /* Hide contact info on mobile - it will be in sidebar */
-  }
-
   .logo {
     width: 60px;
   }
@@ -349,11 +355,6 @@
   .banner-container {
     height: 300px;
   }
-
-  /* Show floating menu button on mobile */
-  .floating-menu-btn {
-    display: flex;
-  }
 }
 
 @media (max-width: 576px) {