Replace sidebar with responsive app shell

src/RolemasterDb.App/Components/Layout/MainLayout.razor

@@ -2,17 +2,9 @@
 @implements IDisposable
 @inject RolemasterDb.App.Frontend.AppState.ThemeState ThemeState
 
-<div class="page">
-    <div class="sidebar">
-        <NavMenu />
-    </div>
-
-    <main>
-        <article class="content-shell">
-            @Body
-        </article>
-    </main>
-</div>
+<AppShell>
+    @Body
+</AppShell>
 
 <div id="blazor-error-ui" data-nosnippet>
     An unhandled error has occurred.

src/RolemasterDb.App/Components/Layout/MainLayout.razor.css

@@ -1,38 +1,3 @@
-.page {
-    min-height: 100vh;
-    display: flex;
-    flex-direction: column;
-}
-
-main {
-    flex: 1;
-    min-width: 0;
-}
-
-.sidebar {
-    background:
-        radial-gradient(circle at top, rgba(196, 167, 107, 0.28), transparent 35%),
-        linear-gradient(180deg, #24130d 0%, #3c2415 46%, #130d0b 100%);
-    border-right: 1px solid rgba(196, 167, 107, 0.2);
-}
-
-.content-shell {
-    padding: 1.5rem;
-}
-
-@media (min-width: 641px) {
-    .page {
-        flex-direction: row;
-    }
-
-    .sidebar {
-        width: 290px;
-        height: 100vh;
-        position: sticky;
-        top: 0;
-    }
-}
-
 #blazor-error-ui {
     color-scheme: light only;
     background: #682e24;