ADD joins two number cards on movement, as printed

"You may add two NUMBER cards together for any single action" —
movement included. The engine accepts a second movement number when an
ADD accompanies it (once per turn); the client spends your Add
automatically and says so on the button. 120 tests passing.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

packages/web/src/App.svelte

@@ -149,8 +149,17 @@
   ]);
 
   function playNumberForMovement() {
-    if (!selectedCard) return;
-    net.command({ type: "playNumberForMovement", instanceId: selectedCard.instanceId });
+    if (!selectedCard || !view) return;
+    const cmd: Parameters<typeof net.command>[0] = {
+      type: "playNumberForMovement",
+      instanceId: selectedCard.instanceId,
+    };
+    // A second movement number needs an ADD — spend one from hand automatically.
+    if (view.turn.numberPlayedForMovement) {
+      const add = view.yourHand.find((c) => c.cardId === "add");
+      if (add) cmd.addInstanceId = add.instanceId;
+    }
+    net.command(cmd);
     clearSelection();
   }
 
@@ -592,7 +601,7 @@
             {/if}
             {#if selectedCard && isNumberCard(selectedCard.cardId)}
               <button class="stamp tiny" onclick={playNumberForMovement}>
-                Play for +{cardDef(selectedCard.cardId).value} movement
+                Play for +{cardDef(selectedCard.cardId).value} movement{view.turn.numberPlayedForMovement ? " (uses your Add)" : ""}
               </button>
             {/if}
             <button class="hint-cancel" onclick={clearSelection}>cancel</button>