feat: enhance UI, branding assets, onboarding flow, and screen layouts

lib/widgets/krow_wordmark.dart

@@ -0,0 +1,78 @@
+import 'package:flutter/material.dart';
+
+import '../core/theme.dart';
+
+/// The brand wordmark.
+///
+/// The asset is an alpha mask — the shape lives in the alpha channel — so one
+/// file tints to any colour. `Image.asset` blends a `color` with `srcIn` by
+/// default, which is the same thing the brand sheet did with a CSS mask.
+///
+/// Sized by width, because the mark is a fixed 3.06:1 and the width is what
+/// has to sit within a layout.
+class KrowWordmark extends StatelessWidget {
+  const KrowWordmark({super.key, this.width = 132, this.color});
+
+  final double width;
+  final Color? color;
+
+  @override
+  Widget build(BuildContext context) {
+    return Image.asset(
+      'assets/images/krow_logo.png',
+      width: width,
+      color: color ?? KrowPalette.yellow,
+      filterQuality: FilterQuality.medium,
+      semanticLabel: 'KROW',
+    );
+  }
+}
+
+/// The line that tops each main tab: the wordmark on the left, and whatever
+/// that tab already had up there on the right — an action button, or its
+/// caption. Putting the mark on the existing line rather than a new one keeps
+/// the brand consistent across tabs without spending header height on it.
+class HeaderBrandLine extends StatelessWidget {
+  const HeaderBrandLine({super.key, this.trailing});
+
+  final Widget? trailing;
+
+  @override
+  Widget build(BuildContext context) {
+    return Row(
+      children: [
+        // White rather than yellow: the accent is already carrying the avatar
+        // and the money figures, and a third yellow element leads nowhere.
+        const KrowWordmark(width: 62, color: Colors.white),
+        const SizedBox(width: 12),
+        if (trailing != null)
+          Expanded(
+            child: Align(alignment: Alignment.centerRight, child: trailing),
+          ),
+      ],
+    );
+  }
+}
+
+/// The small uppercase caption that sits beside the wordmark on a tab header.
+class HeaderEyebrow extends StatelessWidget {
+  const HeaderEyebrow(this.text, {super.key});
+
+  final String text;
+
+  @override
+  Widget build(BuildContext context) {
+    return Text(
+      text.toUpperCase(),
+      maxLines: 1,
+      overflow: TextOverflow.ellipsis,
+      textAlign: TextAlign.right,
+      style: TextStyle(
+        fontSize: 9.5,
+        letterSpacing: 1.5,
+        fontWeight: FontWeight.w600,
+        color: Colors.white.withValues(alpha: 0.5),
+      ),
+    );
+  }
+}