Replace the landing with the artifact design and rebuild the admin in Ant Design.

Adds consultation leads, section editors, and the one-time content reset for this release.

Co-authored-by: Cursor <cursoragent@cursor.com>

apps/landing/composables/useTheme.ts

@@ -0,0 +1,22 @@
+const STORAGE_KEY = "montech_theme";
+
+/** The initial class is applied by the inline boot script in `nuxt.config.ts` before first paint. */
+export function useTheme() {
+  const isDark = useState("theme-dark", () => false);
+
+  function sync() {
+    isDark.value = document.documentElement.classList.contains("dark");
+  }
+
+  function toggle() {
+    isDark.value = !isDark.value;
+    document.documentElement.classList.toggle("dark", isDark.value);
+    try {
+      localStorage.setItem(STORAGE_KEY, isDark.value ? "dark" : "light");
+    } catch {
+      /* storage unavailable (private mode) */
+    }
+  }
+
+  return { isDark, sync, toggle };
+}