🐛 Fix double rotation negation in adjust-shape-flips

When both dot-x and dot-y were negative (both axes flipped),
(update :rotation -) was applied twice which cancelled itself out,
leaving rotation unchanged. The intended behaviour is to negate
rotation once per flip, but flipping both axes simultaneously is
equivalent to a 180° rotation and should not alter the stored angle.

Replaced the two separate conditional rotation updates with a single
one gated on (not= (neg? dot-x) (neg? dot-y)) so the rotation is
negated only when exactly one axis is flipped.

Signed-off-by: Andrey Antukh <niwi@niwi.nz>

common/src/app/common/geom/shapes/transforms.cljc

@@ -303,13 +303,13 @@
       (neg? dot-x)
       (update :flip-x not)
 
-      (neg? dot-x)
-      (update :rotation -)
-
       (neg? dot-y)
       (update :flip-y not)
 
-      (neg? dot-y)
+      ;; Negate rotation only when an odd number of axes are flipped,
+      ;; since flipping both axes is equivalent to a 180° rotation and
+      ;; two negations would cancel each other out.
+      (not= (neg? dot-x) (neg? dot-y))
       (update :rotation -))))
 
 (defn- apply-transform-move