feat(home): 启动页停留至首页就绪

lib/pages/home/home_view.dart

@@ -37,6 +37,11 @@ class HomePage extends StatefulWidget {
 }
 
 class _HomePageState extends State<HomePage> with WidgetsBindingObserver {
+  static const _androidSplashAsset = 'assets/icon/splash_logo_android12.png';
+  static const _defaultSplashAsset = 'assets/icon/splash_logo.png';
+  static const _androidSplashSize = 288.0;
+  static const _defaultSplashSize = 384.0;
+
   bool _resumeRetryInFlight = false;
 
   @override
@@ -100,15 +105,7 @@ class _HomePageState extends State<HomePage> with WidgetsBindingObserver {
     AppLocalizations l10n,
   ) {
     if (catalog.loading) {
-      return AnnotatedRegion<SystemUiOverlayStyle>(
-        value: SystemUiOverlayStyle.light,
-        child: const Scaffold(
-          backgroundColor: AppColors.splashInk,
-          body: Center(
-            child: CircularProgressIndicator(color: AppColors.blue),
-          ),
-        ),
-      );
+      return catalog.settled ? _retryLoading() : _startupSplash();
     }
     if (catalog.error != null) {
       return Scaffold(
@@ -140,6 +137,36 @@ class _HomePageState extends State<HomePage> with WidgetsBindingObserver {
       onRefreshFeed: catalog.refresh,
     );
   }
+
+  Widget _startupSplash() {
+    final isAndroid = defaultTargetPlatform == TargetPlatform.android;
+    final size = isAndroid ? _androidSplashSize : _defaultSplashSize;
+    return AnnotatedRegion<SystemUiOverlayStyle>(
+      value: SystemUiOverlayStyle.light,
+      child: ColoredBox(
+        color: AppColors.splashInk,
+        child: Center(
+          child: Image.asset(
+            isAndroid ? _androidSplashAsset : _defaultSplashAsset,
+            key: const Key('startup-splash'),
+            width: size,
+            height: size,
+            fit: BoxFit.contain,
+          ),
+        ),
+      ),
+    );
+  }
+
+  Widget _retryLoading() {
+    return AnnotatedRegion<SystemUiOverlayStyle>(
+      value: SystemUiOverlayStyle.light,
+      child: const Scaffold(
+        backgroundColor: AppColors.splashInk,
+        body: Center(child: CircularProgressIndicator(color: AppColors.blue)),
+      ),
+    );
+  }
 }
 
 /// 首页目录加载失败与重试入口。