fix(card_drag): extend drop rects one trailing row so beyond-extent drops land

computeSlotRectsForDrop adds cols slots past maxSlot; classifyCardDrag and
drawCardDropTarget use it instead of the render rects. doReorderDrop already
accepts any non-negative slot. New tests cover beyond-extent resolves,
empty-bank trailing row, gap pixels still miss, empty-cell within-extent works.

src/bank_panel.cpp

@@ -1411,7 +1411,13 @@ void drawCardDropTarget(LICE_IBitmap* bmp, const RECT& region, bool isBanks, Reg
 
     const RECT grid = regionGridRect(region, isBanks);
     const RegionDisplay disp = regionDisplay(region, isBanks, reg);
-    for (const SlotCellRect& r : disp.slotRects) {
+    // Use the drop rects (includes the trailing row past maxSlot) so a beyond-extent
+    // target slot gets a visible highlight cue, not silence.
+    const int gridW = grid.right - grid.left;
+    const int maxSlot = disp.bank ? disp.bank->slots.maxSlot() : -1;
+    std::vector<SlotCellRect> dropRects = computeSlotRectsForDrop(maxSlot, gridW, kGrid);
+    for (SlotCellRect& r : dropRects) { r.x += grid.left; r.y += grid.top; }
+    for (const SlotCellRect& r : dropRects) {
         if (r.slot != g_panel.dragTargetSlot) continue;
         if (r.y >= grid.bottom) return;  // below the viewport (no scroll)
         const LICE_pixel hot = toLice(roleColor(Role::AccentHot));
@@ -2738,11 +2744,21 @@ void classifyCardDrag(int x, int y) {
     if (!destBank.empty() && destBank == g_panel.dragSourceBankId) {
         // Same-bank grid: a reorder/replace target. Resolve the slot the pointer sits over
         // in the SOURCE bank's own region display + whether it is occupied.
+        // Uses computeSlotRectsForDrop (one trailing row past maxSlot) so a drop beyond
+        // the last occupied card resolves to a valid trailing slot, not a -1 miss.
         mods.region = DropRegion::SameBankGrid;
         const bool isBanks = g_panel.dragSourceRegion == Region::Banks;
         const RECT region = isBanks ? banksRegionRect(w, h) : poolRegionRect(w, h);
         const RegionDisplay disp = regionDisplay(region, isBanks, g_panel.dragSourceRegion);
-        const int slot = hitTestSlot(x, y, disp.slotRects);
+        const RECT grid = regionGridRect(region, isBanks);
+        const int gridW = grid.right - grid.left;
+        const std::vector<SlotCellRect> dropRects =
+            computeSlotRectsForDrop(disp.bank ? disp.bank->slots.maxSlot() : -1,
+                                    gridW, kGrid);
+        // Translate the drop rects to client space (matching regionDisplay's translation).
+        std::vector<SlotCellRect> dropRectsClient = dropRects;
+        for (SlotCellRect& r : dropRectsClient) { r.x += grid.left; r.y += grid.top; }
+        const int slot = hitTestSlot(x, y, dropRectsClient);
         mods.targetSlot   = slot;
         mods.slotOccupied = slot >= 0 && !disp.idAtSlot(slot).empty();
         g_panel.dragTargetSlot = slot;