fix: fixed statusbar at bottom, fix dropdown toggle race, fix theme buttons on iOS

- StatusBar now uses fixed positioning at viewport bottom (z-[99])
- Dropdown toggle uses skip_next_close guard to prevent close-then-reopen
- Global close listener uses click instead of pointerdown (fires after toggle)
- Theme/limit buttons use on:pointerdown instead of on:click for iOS compat
- Main content has pb-8 to prevent overlap with fixed statusbar
- Rebuilt tailwind.css

frontend/public/tailwind.css

@@ -1366,6 +1366,9 @@
   .right-0 {
     right: calc(var(--spacing) * 0);
   }
+  .bottom-0 {
+    bottom: calc(var(--spacing) * 0);
+  }
   .bottom-full {
     bottom: 100%;
   }
@@ -2172,6 +2175,9 @@
   .pt-1 {
     padding-top: calc(var(--spacing) * 1);
   }
+  .pb-8 {
+    padding-bottom: calc(var(--spacing) * 8);
+  }
   .pb-20 {
     padding-bottom: calc(var(--spacing) * 20);
   }