brand: de-cake new-ui asset filenames + drop unused cake art

Rename the new-ui assets (source in res/pictures + compiled .svg.vec in
assets/new-ui) and their 3 code refs. Content was already Hash Bags; only the
filenames were cake:
- cake_squircle_icon      -> hash_squircle_icon   (About page)
- cakewallet-wordmark(.light) -> hash-wordmark(.light) (receive QR)
- cake-setting            -> hash-setting          (settings)

Remove unused cake assets (0 refs): by-cakelabs, cakelabs-icon, new-ui cupcake
duplicate, cake_icon.png, cake_wordmark.png. (assets/images/cupcake* kept — that
is Cake's Cupcake hardware-signer device name, a real integration, not branding.)

lib/new-ui/pages/about_page.dart

@@ -70,7 +70,7 @@ class _AboutPageState extends State<AboutPage> {
                     GestureDetector(
                       onTap: _easterEgg,
                       child: HashImageWidget(
-                        imageUrl: "assets/new-ui/cake_squircle_icon.svg",
+                        imageUrl: "assets/new-ui/hash_squircle_icon.svg",
                         width: 128,
                         height: 128,
                       ),

lib/new-ui/pages/settings_page.dart

@@ -62,7 +62,7 @@ class SettingsSectionData {
   ]);
 
   static SettingsSectionData appSettings =
-      SettingsSectionData(S.current.app_settings, "assets/new-ui/cake-setting.svg", [
+      SettingsSectionData(S.current.app_settings, "assets/new-ui/hash-setting.svg", [
     SettingsListItem("assets/new-ui/settings_row_icons/connections.svg", S.current.connections, Routes.connectionSync),
     // SettingsListItem("assets/new-ui/settings_row_icons/defaults.svg", "Defaults", ""),
     SettingsListItem("assets/new-ui/settings_row_icons/display.svg", S.current.display, Routes.displaySettingsPage),

lib/new-ui/widgets/receive_page/receive_qr_code.dart

@@ -44,8 +44,8 @@ class ReceiveQrCode extends StatelessWidget {
               opacity: largeQrMode ? 1 : 0,
               child: HashImageWidget(imageUrl:
                 isLightMode
-                    ? "assets/new-ui/cakewallet-wordmark-light.svg"
-                    : "assets/new-ui/cakewallet-wordmark.svg",
+                    ? "assets/new-ui/hash-wordmark-light.svg"
+                    : "assets/new-ui/hash-wordmark.svg",
                 height: 45,
               )),
         ),

res/pictures/cakelabs-icon.svg

@@ -1,10 +0,0 @@
-<svg width="16" height="16" viewBox="0 0 16 16" fill="none" xmlns="http://www.w3.org/2000/svg">
-<g clip-path="url(#clip0_10479_24333)">
-<path fill-rule="evenodd" clip-rule="evenodd" d="M13.4082 0.0086423C13.5514 -0.0183367 13.6995 0.018486 13.8135 0.110205C13.9311 0.205113 13.9999 0.348586 14 0.499853V9.02231C13.9999 9.15486 13.9471 9.2821 13.8535 9.37583L7.38574 15.8534C7.29206 15.9472 7.16471 15.9999 7.03223 15.9999C6.89994 15.9998 6.77329 15.947 6.67969 15.8534L2.14648 11.3133C2.05286 11.2195 2 11.0925 2 10.9598V2.90024C2 2.66499 2.16403 2.46106 2.39355 2.41099L13.3945 0.011572L13.4082 0.0086423ZM7.52344 11.6708L7.52637 14.2958L13.001 8.81431V5.75962L7.52344 11.6708ZM2.99902 3.30259V10.7528L6.52734 14.286L6.52051 7.47446C6.52049 7.45938 6.52312 7.44429 6.52441 7.42954C6.52573 7.41453 6.52663 7.39949 6.5293 7.38462C6.53206 7.36924 6.53689 7.35455 6.54102 7.3397C6.54555 7.32335 6.54944 7.30679 6.55566 7.29087C6.56311 7.27189 6.57242 7.25394 6.58203 7.23618C6.58714 7.22672 6.59189 7.21705 6.59766 7.20786C6.61454 7.18098 6.63374 7.15578 6.65527 7.13267L12.0479 1.32798L2.99902 3.30259ZM7.51953 7.67075L7.52148 10.201L13.001 4.28892V1.77134L7.51953 7.67075Z" fill="#8C9FBB"/>
-</g>
-<defs>
-<clipPath id="clip0_10479_24333">
-<rect width="16" height="16" fill="white"/>
-</clipPath>
-</defs>
-</svg>