Revert X-swap: natural order (no image X-flip)

User wanted NO X-swap and NO image X-flip:
- canvasX = (perp + 2.5) * 256 (no negation): east (perp=-2)
  at canvasX 128 (left), west (perp=+2) at canvasX 1152 (right)
- Image drawn with positive width (no X-flip): map content
  reads normally (place names, street names not mirrored)

The X coordinates read in their natural geographic order:
- left = high x (east), right = low x (west)

If the user is observing from a south-facing view (cockpit facing
back), their right is the world's left (east), so they see
high x on their right (world's left). x still reads correctly
when facing the same direction as the flight.

The arrangement is now back to the natural order with no
swapping in either direction.

vendor/clouds3d.js

@@ -337,9 +337,11 @@ function drawTileAt(lng, perp, dx, dz, centerTileX, centerTileY) {
     // UNPACK_FLIP_Y_WEBGL=true inverts V: canvas top -> texture V=1 (top).
     // For lng axis (Y): invert canvasY so lng=+12 (corridor front in
     // N flight) lands at small canvasY (= screen top after flip).
-    // === X-SWAP BUILD v3 === // X-swap: east (perp=-2) -> canvasX 1152 (right)
+    // === NATURAL ORDER BUILD v4 ===
-    // ends up at canvasX > halfPerp area (right side of canvas).
+    // No X-swap: east (perp=-2) -> canvasX 128 (left of canvas),
-    var canvasX = (-perp + halfPerp + 0.5) * GROUND_TILE_SIZE;
+    // west (perp=+2) -> canvasX 1152 (right). Map content is also
+    // not X-flipped, so the user sees the image in normal orientation.
+    var canvasX = (perp + halfPerp + 0.5) * GROUND_TILE_SIZE;
     var canvasY = (lng + halfLong + 0.5) * GROUND_TILE_SIZE;
     if (canvasX < 0 || canvasX >= groundCanvas.width || canvasY < 0 || canvasY >= groundCanvas.height) {
         return Promise.resolve(false);