The End gets Pokémon: a dimension zone with Cobblemon's End lines

Adrian, 2026-11-02: the End looked barren. The End is now a zone of its own
(Lv 50-70, world/zones.json -> dimensions; Zones.at returns it anywhere in the
End). tools/zone_spawns.py copies every line Cobblemon spawns in End biomes
into spawn_pool_world/the_end.json, on top of its island home: Beheeyem,
Reuniclus, Metagross; Gothitelle and Sigilyph in End cities; Malamar and
Unown with a Poke Snack. Cobblemon rolls the bucket before the Pokemon and
has these all uncommon or rare, so they move to the common bucket with even
line weights (Metagross a fifth).

Self-test end_has_spawns: the main island is in the_end and offers only End
spawns, some in the common bucket. Self-tests and the island check pass.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

docs/design.md

@@ -290,6 +290,8 @@ Self-tests (`BossTests`): every guardian has a fight and a Cobblemon model; each
 
 **Eternatus** replaces the Ender Dragon: the dragon no longer spawns; Eternatus (uncatchable, Lv 80, scaled down to fit) appears on the main End island while a player is there, and beating it does what killing the dragon did (exit portal, gateways, the egg on the first win). Only one at a time: it waits until the entities around its spot have loaded before deciding it's missing, and a second copy never joins while the recorded one is alive (Adrian met a second Eternatus on his second visit, 2026-11-02); extra copies left in older worlds are removed.
 
+**The End has Pokémon** (Adrian, 2026-11-02: it looked barren). The End is a zone of its own, "The End", Lv 50–70 (`world/zones.json` → `dimensions`; `Zones.at` returns it anywhere in the End). Every line Cobblemon spawns in End biomes spawns there too, on top of its home on the island: Beheeyem, Reuniclus and Metagross anywhere; Gothitelle and Sigilyph in End cities; Malamar and Unown with a Poké Snack. Gothita had no island home (it only spawns in the End), so it's new. Cobblemon has all of these uncommon or rare, and it rolls the bucket before the Pokémon, so in the End they move to the common bucket or the End would stay nearly empty; each line weighs the same, Metagross a fifth. Being a zone, the End also has level pressure (full experience up to Lv 75, like the Basalt Furnace) and the wild-Pokémon cleanup above Lv 80; Eternatus is exempt as an uncatchable boss. Self-test `end_has_spawns`.
+
 ## Open decisions for Adrian (proceeding with the default, flagged)
 
 | Decision | Default used for now |