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/components/TippenApp.tsx

@@ -27,7 +27,6 @@ import { Stage } from "./tippen/Stage";
 import { BubblesRun } from "./tippen/modes/BubblesRun";
 import { DiveRun } from "./tippen/modes/DiveRun";
 import { FeedRun } from "./tippen/modes/FeedRun";
-import { JellyfishRun } from "./tippen/modes/JellyfishRun";
 import { RaceRun } from "./tippen/modes/RaceRun";
 import type { CreatureId } from "../lib/tippen/aquarium";
 import type { Lesson, ModeId } from "../lib/tippen/curriculum";
@@ -42,12 +41,12 @@ import { bubbleCountFor } from "../lib/tippen/theme";
 type Screen = "aquarium" | "map" | "run";
 
 /** What a mode is handed to draw - see the original App.tsx for why there are only two
- * shapes for five modes. */
+ * shapes for four modes. */
 type RunTarget =
   | { kind: "letters"; letters: readonly string[] }
   | { kind: "text"; chunks: readonly string[]; text: string; spaceActive: boolean };
 
-const LETTER_ONLY_MODES: readonly ModeId[] = ["bubbles", "jellyfish"];
+const LETTER_ONLY_MODES: readonly ModeId[] = ["bubbles"];
 
 const SHARE_FOR_EMPHASIS: Record<"isolated" | "mixed", number> = { isolated: 0.75, mixed: 0.4 };
 
@@ -315,11 +314,7 @@ export function TippenApp({ onExit }: Props) {
       {screen === "run" && lesson && run && (
         <>
           {run.kind === "letters" ? (
-            mode === "jellyfish" ? (
-              <JellyfishRun {...letterProps(run.letters)} />
-            ) : (
-              <BubblesRun {...letterProps(run.letters)} />
-            )
+            <BubblesRun {...letterProps(run.letters)} />
           ) : mode === "feed" ? (
             <FeedRun {...textProps(run)} />
           ) : mode === "race" ? (