feat: Prevent placing entities on water and improve land generation

events.js

@@ -1,3 +1,7 @@
+// Track mouse position for placement indicator
+let lastMouseWorldX = null;
+let lastMouseWorldY = null;
+
 /**********************************************************************
  * PAN & ZOOM
  **********************************************************************/
@@ -20,6 +24,13 @@ function setupPanZoom() {
       lastMouseX = e.clientX;
       lastMouseY = e.clientY;
     }
+    
+    // Update world coordinates for placement indicator
+    const rect = canvas.getBoundingClientRect();
+    let cx = e.clientX - rect.left;
+    let cy = e.clientY - rect.top;
+    lastMouseWorldX = (cx - (canvas.width/2) - offsetX) / scale;
+    lastMouseWorldY = (cy - (canvas.height/2) - offsetY) / scale;
   });
   
   canvas.addEventListener('wheel', (e) => {
@@ -127,6 +138,12 @@ function setupCanvasClick() {
     let worldX = (cx - (canvas.width/2) - offsetX) / scale;
     let worldY = (cy - (canvas.height/2) - offsetY) / scale;
 
+    // Check if the placement is valid (not in water)
+    if (!isValidPlacement(worldX, worldY)) {
+      logAction("Cannot build on water! Choose a land location.");
+      return;
+    }
+
     switch(purchaseMode) {
       case "House":
         if(money >= COST_HOUSE) {