fix(explore): auto-focus the engagement spine that has event history

apps/escurel-explore/lib/crm/crm_providers.dart

@@ -25,6 +25,36 @@ final allInstancesProvider = FutureProvider<List<InstanceSummary>>((ref) async {
   return out;
 });
 
+/// The instance the workspace auto-focuses on first load: the engagement
+/// spine with the richest *processed* event history (the populated
+/// showcase), falling back to the first spine, then the first instance.
+/// `null` only when the tenant has no instances.
+///
+/// Ranking by `list_events` length is deliberate: the corpus carries
+/// several `spine: true` engagements but assigns *processed* history to
+/// only one — the others' events sit in the inbox, so focusing them
+/// would open an empty event view (no SOURCES filter, no timeline). A
+/// few `list_events` calls on first load buy a deterministic landing on
+/// the populated spine regardless of instance ordering.
+final autoFocusTargetProvider = FutureProvider<String?>((ref) async {
+  final all = await ref.watch(allInstancesProvider.future);
+  if (all.isEmpty) return null;
+  final spines =
+      all.where((i) => i.skill == 'engagement' && i.id.contains('spine')).toList();
+  if (spines.isEmpty) return all.first.id;
+  final client = ref.watch(escurelClientProvider);
+  var bestId = spines.first.id;
+  var bestCount = -1;
+  for (final s in spines) {
+    final count = (await client.listEvents(s.id)).length;
+    if (count > bestCount) {
+      bestCount = count;
+      bestId = s.id;
+    }
+  }
+  return bestId;
+});
+
 /// Layout state for the resizable/collapsible two-pane split: the left
 /// pane's width fraction, and per-pane collapse flags.
 final leftPaneFractionProvider = StateProvider<double>((ref) => 0.42);

apps/escurel-explore/lib/crm/crm_workspace.dart

@@ -31,18 +31,15 @@ class _CrmWorkspaceState extends ConsumerState<CrmWorkspace> {
 
   @override
   Widget build(BuildContext context) {
-    // Land on a populated view: auto-focus the engagement spine (else
-    // the first instance) once on first load.
+    // Land on a populated view: auto-focus the engagement spine with
+    // real processed event history (see autoFocusTargetProvider) once on
+    // first load.
     if (!_autoFocused && ref.watch(currentPageIdProvider) == null) {
-      ref.watch(allInstancesProvider).whenData((all) {
-        if (_autoFocused || all.isEmpty) return;
+      ref.watch(autoFocusTargetProvider).whenData((target) {
+        if (_autoFocused || target == null) return;
         _autoFocused = true;
-        final pick = all.firstWhere(
-          (i) => i.skill == 'engagement' && i.id.contains('spine'),
-          orElse: () => all.first,
-        );
         WidgetsBinding.instance.addPostFrameCallback((_) {
-          if (mounted) ref.read(currentPageIdProvider.notifier).state = pick.id;
+          if (mounted) ref.read(currentPageIdProvider.notifier).state = target;
         });
       });
     }