fix(mobile): improve viewport framing and ignore screenshots

Adjust 2D bounds padding and portrait 3D FOV behavior to reduce mobile cropping, and ignore local screenshots artifacts in git.

src/geometry.js

@@ -65,11 +65,13 @@ export function mechanismBounds() {
     maxX = Math.max(maxX, p.x);
     maxY = Math.max(maxY, p.y);
   }
-  const pad = 30;
+  // Increase padding to account for full range of motion and potential parameter changes
+  const padX = 50;
+  const padY = 60;
   return {
-    minX: minX - pad,
-    minY: minY - pad,
-    maxX: maxX + pad,
-    maxY: maxY + pad,
+    minX: minX - padX,
+    minY: minY - padY,
+    maxX: maxX + padX,
+    maxY: maxY + padY,
   };
 }