dashboard: nest the dropped-NC detail under the NC row

The detail block was rendered after *all* health rows, so it dangled below
the new model: row instead of the NC: row it explains — its indentation read
as broken. Build it into health_rows right after the NC row, with a tree
marker (↳ dropped (only 1 pin on the net):) and consistent nesting.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/tui/screen_dashboard.cpp

@@ -149,6 +149,26 @@ Component Tui::BuildDashboardScreen() {
           "NC:      " + std::to_string(orph_total) + " orphan pin(s) ("
           + std::to_string(orph_imported) + " imported, "
           + std::to_string(orph_dropped) + " dropped)"));
+      // Detail nested directly under the NC row it explains. "dropped" = the
+      // pin was the only one on its net, so essim detached it (a heuristic;
+      // listing them lets the user spot a false positive). Imported NCs were
+      // explicit in the netlist, so they are not expanded.
+      if (orph_dropped > 0) {
+          health_rows.push_back(
+              text("        ↳ dropped (only 1 pin on the net):") | dim);
+          for (auto &dkv : dropped_by_module) {
+              std::sort(dkv.second.begin(), dkv.second.end(), NaturalLess);
+              std::string csv;
+              for (size_t i = 0; i < dkv.second.size(); ++i) {
+                  if (i) csv += ", ";
+                  csv += dkv.second[i];
+              }
+              health_rows.push_back(hbox({
+                  text("            " + dkv.first + ": ") | bold,
+                  text(csv) | dim,
+              }));
+          }
+      }
 
       // Model-driven checks (BSDL pin specs, JTAG chain, source conflicts),
       // reusing the nets computed above.
@@ -253,27 +273,6 @@ Component Tui::BuildDashboardScreen() {
       lines.push_back(separator());
       lines.push_back(text("  Health") | bold);
       for (auto &h : health_rows) lines.push_back(std::move(h));
-      // Detail rows for the dropped-singleton NCs. Imported NCs are not
-      // expanded — they were already explicit in the netlist. Dropped NCs
-      // come from a heuristic, so listing them gives the user a chance to
-      // spot a false positive.
-      if (orph_dropped > 0) {
-          lines.push_back(hbox({
-              text("        dropped — net has only 1 pin (NC):") | dim,
-          }));
-          for (auto &dkv : dropped_by_module) {
-              std::sort(dkv.second.begin(), dkv.second.end(), NaturalLess);
-              std::string csv;
-              for (size_t i = 0; i < dkv.second.size(); ++i) {
-                  if (i) csv += ", ";
-                  csv += dkv.second[i];
-              }
-              lines.push_back(hbox({
-                  text("          " + dkv.first + ": ") | bold,
-                  text(csv),
-              }));
-          }
-      }
       lines.push_back(separator());
       lines.push_back(text("  Analysis") | bold);
       lines.push_back(hbox({text("  • ") | dim,