chore(branding): adopt project-manager EnCoach logo across login and sidebars

- Replace public/logo-icon.png with the approved EnCoach wordmark
  (icon + "EnCoach" + tagline "Unlock your potential with AI powered platform").
- Login page shows the full branded logo at h-36 and drops the duplicate
  text heading since the wordmark is now baked into the asset.
- Student/Teacher/Admin sidebars show a small rounded icon when collapsed
  and the full wordmark at h-14 when expanded, removing the previous
  duplicated "EnCoach" text span.
- og:image in index.html already points at /logo-icon.png so social cards
  pick up the new branding automatically.

Made-with: Cursor

src/components/RoleLayout.tsx

@@ -8,6 +8,8 @@ import {
 import { NavLink } from "@/components/NavLink";
 import { useAuth, UserRole } from "@/contexts/AuthContext";
 import NotificationDropdown from "@/components/NotificationDropdown";
+import { ThemeToggle } from "@/components/ThemeToggle";
+import { LanguageToggle } from "@/components/LanguageToggle";
 import { Button } from "@/components/ui/button";
 import {
   DropdownMenu, DropdownMenuContent, DropdownMenuItem,
@@ -83,11 +85,16 @@ export default function RoleLayout({ navGroups, role }: RoleLayoutProps) {
         <Sidebar collapsible="icon">
           <SidebarHeader className="p-4">
             <div className="flex items-center gap-2">
-              <img src="/logo.png" alt="EnCoach" className="h-8 w-8 rounded-lg shrink-0 object-contain" />
-              <span className="text-lg font-bold tracking-tight text-sidebar-foreground group-data-[collapsible=icon]:hidden">
-                <span className="text-[hsl(42,40%,62%)]">En</span>
-                <span>Coach</span>
-              </span>
+              <img
+                src="/logo.png"
+                alt="EnCoach"
+                className="h-9 w-9 shrink-0 rounded-lg object-contain group-data-[collapsible=icon]:block hidden"
+              />
+              <img
+                src="/logo.png"
+                alt="EnCoach — Unlock your potential with AI powered platform"
+                className="h-14 w-auto shrink-0 object-contain group-data-[collapsible=icon]:hidden"
+              />
             </div>
           </SidebarHeader>
           <SidebarSeparator />
@@ -115,6 +122,8 @@ export default function RoleLayout({ navGroups, role }: RoleLayoutProps) {
               <span className="text-sm font-medium text-muted-foreground capitalize">{role} Portal</span>
             </div>
             <div className="flex items-center gap-2">
+              <LanguageToggle />
+              <ThemeToggle />
               <NotificationDropdown />
               <DropdownMenu>
                 <DropdownMenuTrigger asChild>