Remove the Quallenalarm (jellyfish) typing minigame

Letters-round lessons only had bubbles and jellyfish as eligible arcade
modes; with jellyfish gone, bubbles is now always used instead of the
two alternating - no lessons need to be dropped.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

web/src/lib/tippen/theme.ts

@@ -31,9 +31,9 @@ export const SPEECH_DEFAULT = true;
 
 export const SOUND_DEFAULT = true;
 
-/** How many letters one bubbles or jellyfish round sends up - matched to the dive
- * mode's length so a mode swap is not also a difficulty swap. Dive-mode line length
- * lives on the lesson itself (`lengthFor` in lib/curriculum.ts). */
+/** How many letters one bubbles round sends up - matched to the dive mode's length so a
+ * mode swap is not also a difficulty swap. Dive-mode line length lives on the lesson
+ * itself (`lengthFor` in lib/curriculum.ts). */
 export function bubbleCountFor(world: number): number {
   return world === 1 ? 50 : 100;
 }