resolve keyboard shortcuts through one action table instead of a switch

The controls panel needs to say what each key does right now, and a panel that
keeps its own list of that is a list that goes stale. So the list moves into
lib/core/ControlAction.h: which actions exist, what each is bound to, and when
each does something. InputMapper stops deciding that and switches on the
resolved action instead, so the panel and the key handling cannot disagree
about what Q means -- there is only one place that says.

The table declares; it never performs. It holds no simulation access, fires no
events, and names nothing: display strings live in the ui target, which formats
the bindings this hands it, so a badge is rendered from the real binding rather
than typed beside it. What an action *does* stays exactly where it was.

ControlContext is the snapshot the rules read, which is what keeps this
testable without a world. Two of its facts come from BlueprintLibrary, which is
built after the world view and so arrives by setter; one comes from the new
hovered-transfer flag on BuildModeController, resolved once on mouse-move
through the same classifier the click and the ghost colour already use.

Behaviour is unchanged, deliberately. Ctrl still separates the chords and every
other modifier is still ignored, so Shift+A pans as before; matching modifiers
exactly would have silently swallowed those presses. Build hotkeys and F3/F4
stay outside the table -- the first are advertised on the build buttons and
already derive their badges from the handler's own table, the second are
development controls the panel must never offer.

The tests are the point of putting this in lib: every row's bindings must
resolve back to that row's action in that same context, which fails the moment
a shown row and its handler part ways.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01YHcUerKAZKWNvSKJxYKbnG

src/lib/core/BuildModeController.h

@@ -95,6 +95,15 @@ public:
     QPoint           getBlueprintGhostTile() const;
     void             setBlueprintGhostTile(QPoint tile);
 
+    // Whether the ghost under the cursor would hand its settings to the building
+    // already there rather than place anything (REQ-UI-BLUEPRINT-TRANSFER). Classifying
+    // it needs the factory state, so the caller resolves it and stores the answer here,
+    // as with setGhostValidity. Kept here rather than recomputed per reader so the
+    // click, the ghost's colour, and the controls panel cannot disagree about what the
+    // cursor is over.
+    bool isHoveredGhostTransfer() const;
+    void setHoveredGhostTransfer(bool transfer);
+
     // --- deconstruct mode -----------------------------------------------------
     const std::optional<BuildingId>& getDeconstructHoverBuildingId() const;
     void setDeconstructHoverBuildingId(std::optional<BuildingId> id);
@@ -118,6 +127,7 @@ private:
 
     Blueprint m_blueprint;
     QPoint    m_blueprintGhostTile;
+    bool      m_hoveredGhostIsTransfer = false;
 
     std::optional<BuildingId> m_deconstructHoverBuildingId;
 };