pos changes

lib/core/widgets/brand_mark.dart

@@ -0,0 +1,66 @@
+import 'package:flutter/material.dart';
+
+import '../constants/asset_paths.dart';
+import '../theme/app_colors.dart';
+
+/// The Nearle mark on its tile.
+///
+/// Every surface that shows the brand — login, sidebar, cashier header —
+/// renders this, so the mark cannot drift between them. It replaces the
+/// hand-drawn letter "N" in a gradient box that each of those screens used to
+/// build for itself.
+class BrandMark extends StatelessWidget {
+  const BrandMark({
+    super.key,
+    this.size = 36,
+    this.radius,
+    this.onDark = false,
+  });
+
+  final double size;
+  final double? radius;
+
+  /// Set on a coloured background, where the tile needs no border to separate
+  /// it from what is behind.
+  final bool onDark;
+
+  @override
+  Widget build(BuildContext context) {
+    final corner = BorderRadius.circular(radius ?? size * 0.28);
+
+    return Container(
+      width: size,
+      height: size,
+      // Clipped, not padded: the mark fills the tile edge to edge and the
+      // rounded corner does the trimming, so nothing can spill past the box
+      // whatever aspect ratio the file happens to have.
+      clipBehavior: Clip.antiAlias,
+      decoration: BoxDecoration(
+        color: Colors.white,
+        borderRadius: corner,
+        border: onDark ? null : Border.all(color: AppColors.border),
+      ),
+      child: Image.asset(
+        AssetPaths.logo,
+        fit: BoxFit.fill,
+        width: size,
+        height: size,
+        filterQuality: FilterQuality.medium,
+        // A missing or undeclared asset would otherwise blank the brand out
+        // of the sidebar entirely; the letterform is a poor substitute but a
+        // better failure than nothing.
+        errorBuilder: (context, _, __) => FittedBox(
+          fit: BoxFit.contain,
+          child: Text(
+            'N',
+            style: TextStyle(
+              color: AppColors.primary,
+              fontWeight: FontWeight.w800,
+              fontSize: size,
+            ),
+          ),
+        ),
+      ),
+    );
+  }
+}