Aero goes underwater with rising bubbles; floating cookie notice; Czech title

Frutiger Aero, closer to the mock:
- The scene is water now: sun shafts through a bright surface, caustic
  patches, reeds on the left, a city silhouette on the right, and ten soap
  bubbles that actually rise (own keyframes, varied sizes/speeds/sway; the
  spans are display:none outside aero so they cost nothing elsewhere, and
  they sit still under reduced motion).
- Pale blue glass at 0.8: still reads as glass, but dark navy text clears
  4.5:1 over the water. The phone tab bar mixes the sheet glass instead of
  the page — in aero the page *is* the water, which left its labels at 3.9:1.
- The aero page-level text (muted/subtle) is much darker for the same reason.
- The PWA status bar follows the new water blue (#2fa7e6).

The cookie notice is floating glass now (blurred backdrop, rim, shadow): as a
plain card it read as part of the page background instead of a notice.

Czech: "Tvoje mraznička" -> "Tvůj mrazák" (library title), test updated.

Contrast: 0 below-minimum findings and 0 axe violations across every screen,
all three themes. Version 0.2.1, SW -> freezmo-v55.

components/IceBackdrop.tsx

@@ -31,6 +31,18 @@ export function IceBackdrop() {
       <span className="ice-orb ice-orb-3" />
       <span className="ice-orb ice-orb-4" />
       <span className="ice-orb ice-orb-5" />
+      {/* Aero-only bubbles: display:none unless the aero theme is on, so they
+          cost nothing in the other themes (see .ice-bubble in globals.css). */}
+      <span className="ice-bubble ice-bubble-1" />
+      <span className="ice-bubble ice-bubble-2" />
+      <span className="ice-bubble ice-bubble-3" />
+      <span className="ice-bubble ice-bubble-4" />
+      <span className="ice-bubble ice-bubble-5" />
+      <span className="ice-bubble ice-bubble-6" />
+      <span className="ice-bubble ice-bubble-7" />
+      <span className="ice-bubble ice-bubble-8" />
+      <span className="ice-bubble ice-bubble-9" />
+      <span className="ice-bubble ice-bubble-10" />
       <span className="ice-grain" />
     </div>
   );