Refresh selected-building panel when paused player commands drain

Option A made the per-tick refresh authoritative for the shipyard layout
preview and Configure Layout button, but that path is driven by
TickAdvancedEvent, which only fires while the game is running. Choosing a
schematic while paused therefore still left the widgets hidden until the
game was unpaused or the building re-selected, because the queued
SetRecipeCommand drains on the next frame but no tick advances.

Emit a new PlayerCommandsAppliedEvent from GameWorldView::onFrame once per
frame when queued commands were drained, and have SelectedBuildingPanel
refresh its selection display in response. This is a presentation-only
notification: it is emitted only on the live path (not during replay
playback), touches neither the command queue nor the simulation, and its
only handler never enqueues commands -- so replay recording and
determinism are unaffected.

Factor the former TickAdvancedEvent handler body into
refreshSelectionDisplay() and call it from both handlers to avoid
duplication.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01DyCu8vwChKMbLJQ3xosYEN

src/lib/eventsystem/event/CMakeLists.txt

@@ -31,6 +31,7 @@ SET(HDRS
 	${CMAKE_CURRENT_SOURCE_DIR}/BeamFiredEvent.h
 	${CMAKE_CURRENT_SOURCE_DIR}/DebugDrawToggledEvent.h
 	${CMAKE_CURRENT_SOURCE_DIR}/CommandRequestedEvent.h
+	${CMAKE_CURRENT_SOURCE_DIR}/PlayerCommandsAppliedEvent.h
 	PARENT_SCOPE
 )
 

src/lib/eventsystem/event/PlayerCommandsAppliedEvent.h

@@ -0,0 +1,13 @@
+#pragma once
+
+#include "Event.h"
+
+// Emitted by GameWorldView once per frame after queued player commands have been
+// drained and applied to the simulation. It lets presentation widgets refresh
+// even while the game is paused (no tick advances, so no TickAdvancedEvent), for
+// example so a shipyard's layout preview appears immediately after its schematic
+// is chosen. It is a UI notification only and never feeds back into the command
+// queue, so it has no effect on replay recording or determinism.
+class PlayerCommandsAppliedEvent : public Event
+{
+};

src/ui/GameWorldView.cpp

@@ -62,6 +62,7 @@
 #include "ExpansionCostChangedEvent.h"
 #include "GameSpeedChangedEvent.h"
 #include "SchematicChoicesAvailableEvent.h"
+#include "PlayerCommandsAppliedEvent.h"
 #include "TickAdvancedEvent.h"
 
 namespace
@@ -212,6 +213,7 @@ void GameWorldView::onFrame()
         // Drain queued player commands once per frame, before the tick batch. This
         // runs even at 0x so a paused player sees placed construction sites
         // immediately, while staying deterministic (see docs/replay_design.md).
+        const bool commandsApplied = m_commandManager.hasPending();
         m_commandManager.drain();
 
         // A drained Reset reinitialized the simulation; reset the view to match.
@@ -221,6 +223,17 @@ void GameWorldView::onFrame()
             resetForNewGame();
         }
 
+        // Notify presentation widgets that queued commands were applied, so a
+        // paused player still sees the effect (e.g. a shipyard's layout preview
+        // after picking a schematic) even though no tick advances. UI-only: this
+        // does not touch the command queue or simulation, so replay recording
+        // and determinism are unaffected.
+        if (commandsApplied)
+        {
+            EventManager::getInstance()->sendEventImmediately(
+                std::make_shared<PlayerCommandsAppliedEvent>());
+        }
+
         const int ticks = m_tickDriver.advance(
             static_cast<double>(elapsed), m_gameSpeedMultiplier);
         for (int i = 0; i < ticks; ++i)

src/ui/SelectedBuildingPanel.cpp

@@ -33,6 +33,7 @@
 #include "ItemType.h"
 #include "LayoutDialogRequestedEvent.h"
 #include "ModulesConfig.h"
+#include "PlayerCommandsAppliedEvent.h"
 #include "RecipeSelectionDialog.h"
 #include "RecipeSelectionRequestedEvent.h"
 #include "Rotation.h"
@@ -560,6 +561,21 @@ const ShipDef* SelectedBuildingPanel::findShipDef(const std::string& id) const
 }
 
 void SelectedBuildingPanel::handleEvent(std::shared_ptr<const TickAdvancedEvent> /*event*/)
+{
+    refreshSelectionDisplay();
+}
+
+void SelectedBuildingPanel::handleEvent(
+    std::shared_ptr<const PlayerCommandsAppliedEvent> /*event*/)
+{
+    // Player commands (e.g. choosing a shipyard schematic) are applied by a
+    // queued drain, not synchronously. When the game is paused no tick advances,
+    // so TickAdvancedEvent never fires; refresh here too, otherwise the panel
+    // would not reflect the change until the next tick or a re-selection.
+    refreshSelectionDisplay();
+}
+
+void SelectedBuildingPanel::refreshSelectionDisplay()
 {
     if (m_selectedEntity.has_value())
     {

src/ui/SelectedBuildingPanel.h

@@ -16,6 +16,7 @@
 #include "EntitySelectedEvent.h"
 #include "EventHandler.h"
 #include "GameConfig.h"
+#include "PlayerCommandsAppliedEvent.h"
 #include "RecipesConfig.h"
 #include "SelectionChangedEvent.h"
 #include "ShipLayout.h"
@@ -33,6 +34,7 @@ class QVBoxLayout;
 
 class SelectedBuildingPanel : public QWidget,
                                public CombinedEventHandler<TickAdvancedEvent,
+                                                           PlayerCommandsAppliedEvent,
                                                            EntitySelectedEvent,
                                                            SelectionChangedEvent,
                                                            DebugDrawToggledEvent>
@@ -46,6 +48,7 @@ public:
 
 private:
     void handleEvent(std::shared_ptr<const TickAdvancedEvent> event) override;
+    void handleEvent(std::shared_ptr<const PlayerCommandsAppliedEvent> event) override;
     void handleEvent(std::shared_ptr<const EntitySelectedEvent> event) override;
     void handleEvent(std::shared_ptr<const SelectionChangedEvent> event) override;
     void handleEvent(std::shared_ptr<const DebugDrawToggledEvent> event) override;
@@ -57,6 +60,7 @@ private slots:
 
 private:
     void onSelectionChanged(const std::vector<BuildingId>& ids);
+    void refreshSelectionDisplay();
     void rebuild();
     void hideAllWidgets();
     void clearContent();