Make the lesson map the floor screen of the typing tab

The aquarium was a separate landing screen in front of the map, showing the pets
collected so far and a "Weiter üben" button. But the pets already swim behind
every screen in the tab, so the screen mostly restated what was visible anyway,
at the cost of one extra step between opening the tab and typing.

The map absorbs what was worth keeping: the "Weiter üben" button now floats over
it, and the pets, streak and best animal move into the header. One Escape from
the map leaves the tab entirely, where it used to go back a screen first.

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

web/src/styles/tippen.css

@@ -294,3 +294,19 @@
 .tp-target-char[data-blank="true"] {
   min-width: 0.9em;
 }
+
+/* The world-reward pets, shown small in the map's header: one per world, in colour once
+   it has moved in and as a white silhouette until then. The same "the next thing has to
+   be visible to be worth aiming at" rule as the animal ladder on the result sheet. */
+.tp-map-creatures {
+  display: flex;
+  align-items: center;
+  gap: 4px;
+}
+
+@media (max-width: 520px) {
+  /* The streak and the best animal say more per pixel on a narrow screen. */
+  .tp-map-creatures {
+    display: none;
+  }
+}