Task e0a2b862: Today tab (#192)

admin/src/App.tsx

@@ -1,5 +1,6 @@
 import { useState } from "react";
 import "./App.css";
+import TodayTab from "./today/TodayTab";
 
 const TABS = [
   { id: "today", label: "Today" },
@@ -12,22 +13,29 @@ type TabId = (typeof TABS)[number]["id"];
 
 export default function App() {
   const [active, setActive] = useState<TabId>("today");
+  // Built screens own their header (ADMIN-SPEC §1); the generic shell header
+  // stays for placeholder tabs and is visually hidden otherwise.
+  const hasScreen = active === "today";
 
   return (
     <div className="admin-shell">
-      <header className="admin-header">
+      <header className={hasScreen ? "admin-header visually-hidden" : "admin-header"}>
         <h1 className="admin-title">NestQuest Admin</h1>
         <p className="admin-subline">Admin console</p>
       </header>
       <main
-        className="admin-panel"
+        className={hasScreen ? "admin-panel admin-panel--screen" : "admin-panel"}
         role="tabpanel"
         aria-labelledby={`tab-${active}`}
       >
-        <p className="admin-placeholder">
-          {TABS.find((tab) => tab.id === active)?.label} placeholder — screens
-          arrive in later tasks.
-        </p>
+        {active === "today" ? (
+          <TodayTab />
+        ) : (
+          <p className="admin-placeholder">
+            {TABS.find((tab) => tab.id === active)?.label} placeholder — screens
+            arrive in later tasks.
+          </p>
+        )}
       </main>
       <nav className="admin-tabbar" aria-label="Admin sections">
         {TABS.map((tab) => (