move pan input into an InputMapper

src/ui/GameWorldView.h

@@ -31,6 +31,8 @@
 #include "EventHandler.h"
 #include "ExitBlueprintModeRequestedEvent.h"
 #include "ExitBuilderModeRequestedEvent.h"
+#include "InputMapper.h"
+#include "PanDirectionChangedEvent.h"
 #include "DebugDrawToggledEvent.h"
 #include "ArtifactCountChangedEvent.h"
 #include "BeamFiredEvent.h"
@@ -80,6 +82,7 @@ class GameWorldView : public QOpenGLWidget,
                                                   BlueprintPlacementRequestedEvent,
                                                   ExitBlueprintModeRequestedEvent,
                                                   SpeedChangeRequestedEvent,
+                                                  PanDirectionChangedEvent,
                                                   CommandRequestedEvent>
 {
     Q_OBJECT
@@ -119,6 +122,7 @@ private:
     void handleEvent(std::shared_ptr<const BlueprintPlacementRequestedEvent> event) override;
     void handleEvent(std::shared_ptr<const ExitBlueprintModeRequestedEvent> event) override;
     void handleEvent(std::shared_ptr<const SpeedChangeRequestedEvent> event) override;
+    void handleEvent(std::shared_ptr<const PanDirectionChangedEvent> event) override;
     void handleEvent(std::shared_ptr<const CommandRequestedEvent> event) override;
 
     // Enqueue a sim command onto the CommandManager (the single mutation path).
@@ -392,13 +396,16 @@ private:
     QPoint                m_boxStartTile;
     QPoint                m_boxCurrentTile;
 
-    // Held-key state for the A / D pan controls (REQ-UI-SCROLL, REQ-UI-HOTKEYS),
-    // collapsed into a PanDirection for the camera each frame. Kept here rather
-    // than on the camera because it is key state, not view state: once controls
-    // are rebindable this becomes an input mapper publishing the direction, and
-    // the camera's interface does not change.
-    bool m_scrollLeft;
-    bool m_scrollRight;
+    // Interprets this widget's key events into semantic actions and publishes them
+    // (REQ-UI-HOTKEYS). Owned here for now because this is the widget that holds
+    // focus; everything it produces travels by event, so it can move to a
+    // window-wide owner later without touching its consumers.
+    InputMapper m_inputMapper;
+
+    // Latest pan direction published by the input mapper (REQ-UI-SCROLL), fed to
+    // the camera each frame. Cached from the event payload rather than re-read:
+    // input has no other source of truth (see PanDirectionChangedEvent).
+    PanDirection m_panDirection = PanDirection::None;
     bool m_gameOverShown;
     bool m_winShown;
     bool m_schematicChoiceShown;