fix(ui): home-page nav buffer must size to HomePage::Count after FAVOURITES

Both call sites of buildVisibleOrder wrote into a fixed-size 11-int
stack buffer. After FAVOURITES landed, HomePage::Count became 12; in
the common case where all pages are visible, buildVisibleOrder writes
12 entries — one past the end. That OOB write trashed whatever lived
next on the stack (typically the loop variable in navPage), so LEFT
wrap-around behaved randomly: sometimes locked at the first page,
sometimes jumped to a wrong one. User-visible as "menu doesn't wrap
to the left".

Size the buffer to `(int)Count` so it tracks the enum and grows with
any future home page additions.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

examples/companion_radio/ui-new/UITask.cpp

@@ -280,7 +280,7 @@ class HomeScreen : public UIScreen {
   }
 
   int navPage(int from, int dir) const {
-    int order[11]; int n = buildVisibleOrder(order);
+    int order[(int)Count]; int n = buildVisibleOrder(order);
     if (n == 0) return from;
     int cur = 0;
     for (int i = 0; i < n; i++) if (order[i] == from) { cur = i; break; }
@@ -482,7 +482,7 @@ public:
 
     // curr page indicator — hidden on CLOCK page (full screen used for dashboard)
     if (_page != CLOCK) {
-      int order[11]; int n = buildVisibleOrder(order);
+      int order[(int)Count]; int n = buildVisibleOrder(order);
       int curr_vis = 0;
       for (int i = 0; i < n; i++) if (order[i] == _page) { curr_vis = i; break; }
       int x = display.width() / 2 - 5 * (n - 1);