remove the Shift copy-building-settings gesture

REQ-BLD-COPY-CONFIG is dropped: Shift+right-click no longer caches a
building's recipe / schematic+layout / splitter filters, Shift+left-click
no longer stamps them onto same-type buildings, and the cyan eligible-
target tint and copy/paste flashes go with them. Shift+left-click now
falls through to normal selection, which needs no code of its own -- only
Ctrl is meaningful to selection (REQ-UI-MULTI-SELECT), so dropping the
branch that consumed the click is enough.

readBuildingConfig stays. It had two callers, and the other one is
captureBlueprintFromSelection, which needs it to record each blueprint
building's configuration (REQ-UI-BLUEPRINT-STORAGE). Its five tests stay
too, retagged [blueprint] and rewritten to name the caller that is left.

The visuals.toml copy_config colour is removed together with its
VisualsConfig field and its loader line: overlay keys are mandatory, so
those three have to move as one or startup aborts.

REQ-BLD-COPY-CONFIG-FEEDBACK, cited by four of these files and by the TOML
comment, never existed in requirements.md; deleting the citations retires
a dangling id.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01JcReq7hVk4KUPhTDKWAG7K

src/ui/GameWorldView.h

@@ -20,7 +20,6 @@
 
 #include "Blueprint.h"
 #include "BuildModeController.h"
-#include "BuildingConfig.h"
 #include "BlueprintModeExitedEvent.h"
 #include "BlueprintPlacementRequestedEvent.h"
 #include "BuilderModeExitedEvent.h"
@@ -217,12 +216,6 @@ private:
     // Enqueues placements and rotate-in-place commands for the resolved path.
     void                          applyBeltDragPath();
 
-    // Copy-settings gesture (REQ-BLD-COPY-CONFIG): Shift+right-click copies a
-    // building's configuration into m_copiedConfig; Shift+left-click applies it to
-    // another building of the same type via the existing configuration commands.
-    void     copyConfigFrom(BuildingId id);
-    void     pasteConfigTo(BuildingId id);
-
     // Turns the ghost and refreshes everything that depends on its facing: placement
     // validity, the tunnel completion match, and an in-progress belt drag's path.
     // The mode transitions themselves live on m_buildMode.
@@ -271,17 +264,6 @@ private:
     // and to resolve the tunnel ghost sub-tile (REQ-BLD-TUNNEL-MODE).
     QVector2D                            m_cursorWorldPos;
 
-    // Temporary cache for the copy-settings gesture (REQ-BLD-COPY-CONFIG); held
-    // only while Shift is down and cleared on Shift release.
-    std::optional<BuildingConfig> m_copiedConfig;
-
-    // Brief outline flash shown on a building when settings are copied from it or
-    // pasted onto it (REQ-BLD-COPY-CONFIG-FEEDBACK). remainingMs counts down in
-    // wall-clock time so the flash plays at a fixed length regardless of game speed
-    // (and while paused).
-    std::vector<CopyConfigFlash> m_copyConfigFlashes;
-    static constexpr qint64      kCopyFlashDurationMs = 300;
-
     bool     m_debugDraw;
 
     // Owns the selection across all three categories and the rules for moving