perf: defer initial data fetching to microtasks and update loading placeholders for smoother screen transitions

lib/features/agents/presentation/providers/agent_detail_provider.dart

@@ -449,7 +449,10 @@ class AgentDetailNotifier extends StateNotifier<AgentDetailState> {
 
   AgentDetailNotifier(this._repo, this.agentId)
       : super(const AgentDetailState()) {
-    _load();
+    // Defer the network burst to the next microtask so the agent detail
+    // screen's first frame (loading placeholder) paints before the three
+    // parallel HTTP requests kick off — smoother slide-in transition.
+    Future.microtask(_load);
     // Listen for real-time connection response (accepted/rejected)
     _connectionResponseSub =
         SocketService().onConnectionResponse.listen((_) {

lib/features/agents/presentation/screens/agent_detail_screen.dart

@@ -45,8 +45,21 @@ class _AgentDetailScreenState extends ConsumerState<AgentDetailScreen> {
     final state = ref.watch(agentDetailProvider(widget.agentId));
 
     if (state.isLoading) {
-      return const Center(
-        child: CircularProgressIndicator(color: AppColors.accentOrange),
+      // Full-size placeholder with the screen's base color so the slide-in
+      // transition doesn't pop from blank → content. Small spinner at top
+      // instead of centered (less attention-grabbing during navigation).
+      return Container(
+        color: Colors.white,
+        alignment: Alignment.topCenter,
+        padding: const EdgeInsets.only(top: 120),
+        child: const SizedBox(
+          width: 28,
+          height: 28,
+          child: CircularProgressIndicator(
+            color: AppColors.accentOrange,
+            strokeWidth: 2.5,
+          ),
+        ),
       );
     }
     if (state.error != null) {