Port the special battle types and contest battles

Run the forced-shiny, trap, forced-item, Celebi, Suicune, roaming and Bug-Catching Contest battle types. Roaming battles keep their struct's DVs and HP byte, and every other battle makes CleanUpBattleRAM's roaming roll. The contest shows PARKBALL×, counts down Park Balls, ends when they run out, keeps its catch outside the party and asks before switching. Scripts load the special types with loadvar, and while a contest runs, encounters use BugCatchingContestBattleScript and ContestMons.

Validated with 596 unit tests, 155 browser tests (including the contest menu and switch screen), native/reference builds and reference/vendor/release checks. National Park's contest event, the roaming release and the Ilex Forest Celebi event come with their maps.

Closes #28

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

src/main.ts

@@ -11,6 +11,7 @@ import { LocalMapView } from "./game/rendering/minimap";
 import type { Choice, GameWorld } from "./game/world/world";
 import type { PokegearCard } from "./game/scripts/pokegear";
 import { drawTile } from "./game/rendering/pixels";
+import { C } from "./game/battle/constants";
 import { PokemonData } from "./game/rom/pokemon";
 import type { Direction, Palette } from "./game/world/types";
 import type { Button } from "./input/types";
@@ -589,6 +590,9 @@ function handleFieldInput(button: Button): boolean {
   return true;
 }
 
+/** Battle prompts answered with YES/NO. */
+const yesNoPrompt = (prompt?: { kind: string }) =>
+  prompt?.kind === "yesno" || prompt?.kind === "contestswitch";
 function battleButtons() {
   return [
     ...get("battle-menu").querySelectorAll<HTMLButtonElement>(
@@ -636,7 +640,7 @@ function handleBattleInput(button: Button): boolean {
   if (["up", "down", "left", "right"].includes(button)) {
     const delta = button === "up" || button === "left" ? -1 : 1;
     battleCursor = (battleCursor + delta + buttons.length) % buttons.length;
-    if (world.battle.prompt?.kind === "yesno")
+    if (yesNoPrompt(world.battle.prompt))
       world.battle.selected = battleCursor === 0 ? 1 : 0;
     highlightBattleChoice();
     return true;
@@ -699,7 +703,9 @@ function showBattle(world: GameWorld) {
   get("battle-text").textContent =
     prompt?.kind === "name"
       ? prompt.title
-      : prompt?.kind === "party" || prompt?.kind === "move"
+      : prompt?.kind === "party" ||
+          prompt?.kind === "move" ||
+          prompt?.kind === "contestswitch"
         ? prompt.text
         : (view.message?.text ?? "");
   if (prompt?.kind !== "action") showMoves = showPack = false;
@@ -712,7 +718,7 @@ function showBattle(world: GameWorld) {
     battleCursor = 0;
     battleSelectionKey = selectionKey;
   }
-  if (prompt?.kind === "yesno") battleCursor = view.selected === 1 ? 0 : 1;
+  if (yesNoPrompt(prompt)) battleCursor = view.selected === 1 ? 0 : 1;
   const bag = world.liveState.bag;
   // The Pokémon out has its live battle HP; the others their party values.
   const party = world.liveState.party.map((mon, index) =>
@@ -846,13 +852,45 @@ function showBattle(world: GameWorld) {
           showWorld(world);
         }),
         button("PKMN", () => runtime.battleAction({ action: "pkmn" })),
-        button("PACK", () => {
-          showPack = true;
-          showWorld(world);
-        }),
+        // ContestBattleMenu: PARKBALL× with two digits throws a Park Ball.
+        prompt.parkBalls !== undefined
+          ? button(
+              `PARKBALL×${String(prompt.parkBalls).padStart(2, "0")}`,
+              () =>
+                runtime.battleAction({
+                  action: "item",
+                  item: C.PARK_BALL,
+                  slot: -1,
+                }),
+            )
+          : button("PACK", () => {
+              showPack = true;
+              showWorld(world);
+            }),
         button("RUN", () => runtime.battleAction({ action: "run" })),
       );
     }
+  } else if (prompt?.kind === "contestswitch") {
+    // DisplayCaughtContestMonStats: STOCK and THIS boxes, then Yes/No.
+    for (const [label, mon] of [
+      ["STOCK", prompt.stock],
+      ["THIS", prompt.caught],
+    ] as const)
+      buttons.push(
+        button(`${label} ${mon.name} :L${mon.level}`, () => {}, {
+          detail: `HEALTH ${mon.maxHp}`,
+          disabled: " ",
+          wide: true,
+        }),
+      );
+    buttons.push(
+      button("YES", () => runtime.battleChoose(1), {
+        pressed: view.selected === 1,
+      }),
+      button("NO", () => runtime.battleChoose(0), {
+        pressed: view.selected === 0,
+      }),
+    );
   } else if (prompt?.kind === "yesno") {
     buttons.push(
       button("YES", () => runtime.battleChoose(1), {