✨ Phase 1.1-1.2: Enhance MainLayout & AuthLayout with MudBlazor

Phase 1.1: MainLayout Improvements
✅ Responsive sidebar with mobile toggle (MudDrawer)
✅ Enhanced top navigation (AppBar with icons)
✅ Dark mode toggle with persistence
✅ User profile menu (MudMenu with logout)
✅ Improved theme switching

Features:
- MudThemeProvider integration for dark/light mode
- User avatar with initials
- Profile, Settings, and Logout options in dropdown menu
- Responsive navbar (hidden on mobile, visible on desktop)
- Drawer footer with version info
- Enhanced CSS with smooth transitions

Phase 1.2: AuthLayout Complete Redesign
✅ Two-panel layout (branding + auth content)
✅ Left panel with QuantEngine branding and features
✅ Right panel for login/register/password recovery
✅ Mobile responsive design
✅ Dark mode support with smooth transitions

Features:
- Hero branding panel with feature list
- Feature icons (CheckCircle animations)
- Responsive grid (left panel hidden on mobile)
- Dark mode theme toggle
- Footer with legal links
- Floating animation on logo
- Mobile header with theme toggle
- Accessibility support (prefers-reduced-motion)

Styling Enhancements:
- Modern gradient backgrounds
- Smooth transitions and animations
- Dark mode color schemes
- Responsive breakpoints
- Material Design principles

Files Modified:
- src/dotnet/QuantEngine.Web/Client/Layout/MainLayout.razor
- src/dotnet/QuantEngine.Web/Client/Layout/MainLayout.razor.css
- src/dotnet/QuantEngine.Web/Client/Layout/AuthLayout.razor
- src/dotnet/QuantEngine.Web/Client/Layout/AuthLayout.razor.css (new)

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

src/dotnet/QuantEngine.Web/Client/Layout/MainLayout.razor.css

@@ -1,81 +1,83 @@
-.page {
-    position: relative;
-    display: flex;
-    flex-direction: column;
+/* QuantEngine MainLayout Styles */
+
+/* AppBar Enhancements */
+.mud-appbar-dense {
+    padding: 0 1rem;
 }
 
-main {
+.mud-appbar-dense ::deep .mud-appbar-section-center {
     flex: 1;
 }
 
-.sidebar {
-    background-image: linear-gradient(180deg, rgb(5, 39, 103) 0%, #3a0647 70%);
+/* Avatar Styling */
+::deep .mud-avatar {
+    cursor: pointer;
+    transition: transform 0.2s ease;
 }
 
-.top-row {
-    background-color: #f7f7f7;
-    border-bottom: 1px solid #d6d5d5;
-    justify-content: flex-end;
-    height: 3.5rem;
-    display: flex;
-    align-items: center;
+::deep .mud-avatar:hover {
+    transform: scale(1.05);
 }
 
-    .top-row ::deep a, .top-row ::deep .btn-link {
-        white-space: nowrap;
-        margin-left: 1.5rem;
-        text-decoration: none;
+/* Drawer Footer */
+.mud-drawer-footer {
+    position: absolute;
+    bottom: 0;
+    width: 100%;
+    background: var(--mud-palette-surface);
+}
+
+/* Main Content Area */
+.mud-main-content-enhanced {
+    min-height: 100vh;
+    background: var(--mud-palette-background);
+    transition: background-color 0.3s ease;
+}
+
+/* Navigation Menu Styles */
+.mud-navmenu {
+    padding: 1rem 0;
+}
+
+.mud-navmenu ::deep .mud-nav-item {
+    padding: 0.5rem 0;
+    margin: 0.25rem 0;
+}
+
+.mud-navmenu ::deep .mud-nav-link {
+    border-radius: 0.4rem;
+    margin: 0 0.5rem;
+    transition: all 0.2s ease;
+}
+
+.mud-navmenu ::deep .mud-nav-link:hover {
+    background-color: var(--mud-palette-action-default-hover);
+}
+
+.mud-navmenu ::deep .mud-nav-link.mud-ripple-nav-link-active {
+    background-color: var(--mud-palette-primary-lighten);
+    color: var(--mud-palette-primary);
+    font-weight: 600;
+}
+
+/* Responsive Drawer */
+@media (max-width: 599px) {
+    .mud-drawer-content {
+        width: 100% !important;
     }
 
-    .top-row ::deep a:hover, .top-row ::deep .btn-link:hover {
-        text-decoration: underline;
-    }
-
-    .top-row ::deep a:first-child {
-        overflow: hidden;
-        text-overflow: ellipsis;
-    }
-
-@media (max-width: 640.98px) {
-    .top-row {
-        justify-content: space-between;
-    }
-
-    .top-row ::deep a, .top-row ::deep .btn-link {
-        margin-left: 0;
+    .mud-drawer-footer {
+        position: relative;
     }
 }
 
-@media (min-width: 641px) {
-    .page {
-        flex-direction: row;
-    }
-
-    .sidebar {
-        width: 250px;
-        height: 100vh;
-        position: sticky;
-        top: 0;
-    }
-
-    .top-row {
-        position: sticky;
-        top: 0;
-        z-index: 1;
-    }
-
-    .top-row.auth ::deep a:first-child {
-        flex: 1;
-        text-align: right;
-        width: 0;
-    }
-
-    .top-row, article {
-        padding-left: 2rem !important;
-        padding-right: 1.5rem !important;
+@media (min-width: 600px) {
+    .mud-drawer-footer {
+        position: absolute;
     }
 }
 
+/* Error UI */
 #blazor-error-ui {
     color-scheme: light only;
     background: lightyellow;
@@ -90,9 +92,14 @@ main {
     z-index: 1000;
 }
 
-    #blazor-error-ui .dismiss {
-        cursor: pointer;
-        position: absolute;
-        right: 0.75rem;
-        top: 0.5rem;
-    }
+#blazor-error-ui .dismiss {
+    cursor: pointer;
+    position: absolute;
+    right: 0.75rem;
+    top: 0.5rem;
+}
+
+/* Dark Mode Transitions */
+* {
+    transition: background-color 0.3s ease, color 0.3s ease;
+}