Add app scaffold and workflows

app/frontend/app/globals.css

@@ -0,0 +1,35 @@
+@import "tailwindcss";
+
+@source "./app/**/*.{js,ts,jsx,tsx,mdx}";
+@source "./components/**/*.{js,ts,jsx,tsx,mdx}";
+
+@theme {
+  --color-ink: #0f172a;
+  --color-inkSoft: #1e293b;
+  --color-inkMuted: #64748b;
+  --color-sand: #f7f7fb;
+  --color-card: #ffffff;
+  --color-success: #22c55e;
+  --color-danger: #ef4444;
+  --color-pulse: #f59e0b;
+  --color-accent-blue: #60a5fa;
+  --color-accent-mint: #34d399;
+  --color-accent-coral: #fb7185;
+  --font-sans: "Plus Jakarta Sans", "Inter", system-ui, -apple-system, "Segoe UI",
+    sans-serif;
+  --font-display: "Plus Jakarta Sans", "Inter", system-ui, -apple-system, "Segoe UI",
+    sans-serif;
+}
+
+:root {
+  color-scheme: light;
+  background-color: #f7f7fb;
+}
+
+body {
+  @apply min-h-screen bg-gradient-to-br from-[#f9fafb] via-[#f2f4f6] to-[#e7eaee] text-ink antialiased;
+}
+
+* {
+  @apply selection:bg-blue-200 selection:text-ink;
+}