feat(ui): float the remaining large dialogs (Phase 2 float rollout)

Per the user's selection, convert the large multi-section dialogs to the BlurFloat
style (floating content on the blur, plain heading, no glass card), each KEEPING
its authored width so width-coupled content is untouched:
- Export all keys, Console RPC reference, Explorer block detail
- Updater dialogs: daemon update, xmrig update, bootstrap download (multi-state)

Settings and Address book intentionally kept as cards (the modal Settings *window*
is dead code — show_settings_ is never set; the live Settings surface is the nav
page, not a modal; Address book has a nested edit that reads better contained).
All other confirm/input dialogs stay card-on-blur ("card for small"). Updater
dialogs are multi-state — GUI-check each state (confirm/progress/done/failed).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/ui/windows/explorer_tab.cpp

@@ -1024,7 +1024,11 @@ static void renderBlockDetailModal(App* app) {
         return;
     }
 
-    if (!BeginOverlayDialog(TR("explorer_block_detail"), &s_show_detail_modal, modalW, 0.90f))
+    OverlayDialogSpec ov;
+    ov.title = TR("explorer_block_detail"); ov.p_open = &s_show_detail_modal;
+    ov.style = OverlayStyle::BlurFloat;   // floating content on the blur, plain heading
+    ov.cardWidth = modalW; ov.cardBottomViewportRatio = 0.90f;   // keep authored width
+    if (!BeginOverlayDialog(ov))
         return;
 
     float contentW = ImGui::GetContentRegionAvail().x;