Add shell omnibox foundation

src/RolemasterDb.App/wwwroot/app.css

@@ -820,6 +820,12 @@ pre,
     background: var(--surface-elevated);
 }
 
+.app-bar-action-button:focus-visible,
+.shell-omnibox-result:focus-visible {
+    outline: 2px solid var(--focus-ring);
+    outline-offset: 2px;
+}
+
 .app-bar-action-button:disabled {
     opacity: 0.78;
     cursor: not-allowed;
@@ -949,6 +955,64 @@ pre,
     overflow: auto;
 }
 
+.shell-omnibox-drawer.surface-drawer.is-end {
+    width: min(34rem, calc(100vw - 2rem));
+}
+
+.shell-omnibox-panel {
+    display: grid;
+    gap: 1rem;
+}
+
+.shell-omnibox-search {
+    display: block;
+}
+
+.shell-omnibox-input {
+    width: 100%;
+    min-height: 3rem;
+}
+
+.shell-omnibox-results {
+    display: grid;
+    gap: 0.6rem;
+}
+
+.shell-omnibox-result {
+    display: flex;
+    align-items: center;
+    justify-content: space-between;
+    gap: 1rem;
+    width: 100%;
+    padding: 0.85rem 0.95rem;
+    border: 1px solid var(--border-subtle);
+    border-radius: 1rem;
+    background: color-mix(in srgb, var(--surface-elevated) 86%, transparent);
+    text-align: left;
+}
+
+.shell-omnibox-result:hover {
+    border-color: var(--border-strong);
+    background: var(--surface-elevated);
+}
+
+.shell-omnibox-result-main {
+    display: grid;
+    gap: 0.2rem;
+}
+
+.shell-omnibox-result-main span {
+    color: var(--text-muted);
+}
+
+.shell-omnibox-result-meta {
+    display: inline-flex;
+    align-items: center;
+    gap: 0.45rem;
+    flex-wrap: wrap;
+    justify-content: end;
+}
+
 .details-block {
     margin-top: 0.85rem;
 }
@@ -1991,4 +2055,12 @@ pre,
         flex-direction: column;
         align-items: stretch;
     }
+
+    .shell-omnibox-drawer.surface-drawer.is-end {
+        right: 0.75rem;
+        left: 0.75rem;
+        width: auto;
+        top: calc(var(--shell-header-height) + 0.75rem);
+        bottom: calc(var(--shell-mobile-nav-height) + 0.75rem);
+    }
 }