feat: wire sse_client_cpp_core for live updates from /api/boards/issues/stream

panel_dashboard.cpp

@@ -6,6 +6,7 @@
 
 #include <imgui.h>
 #include <map>
+#include <mutex>
 #include <string>
 
 namespace kanban_cpp {
@@ -30,11 +31,17 @@ void draw_dashboard(AppState& s, bool* p_open) {
     ImGui::TextDisabled("KPIs sinteticos (TODO: backend /api/stats endpoint)");
     ImGui::Separator();
 
+    std::vector<Card> cards_snap;
+    {
+        std::lock_guard<std::mutex> lock(s.mu);
+        cards_snap = s.cards;
+    }
+
     // Snapshot counts
-    int total = static_cast<int>(s.cards.size());
+    int total = static_cast<int>(cards_snap.size());
     std::map<std::string, int> by_priority;
     std::map<std::string, int> by_status;
-    for (const auto& c : s.cards) {
+    for (const auto& c : cards_snap) {
         if (!c.priority.empty()) by_priority[c.priority]++;
         if (!c.status.empty())   by_status[c.status]++;
     }