Integrate battles with the overworld UI and validate browser flows

- Drive wild battles through the real UI in Chromium and WebKit using a
  test-only encounter fixture: victory with level-up, escape, whiteout,
  mid-battle backup restore and unsupported-effect rollback.
- Add keyboard and on-screen D-pad navigation for battle menus.
- Accept pending stat experience in saves (awarded without CalcMonStats).
- Commit whiteout healing, money loss and destination callbacks together;
  aborted scripts restore state and map.
- Give long notices their own status-bar row on narrow screens.

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

src/game/party/pokemon.ts

@@ -181,9 +181,14 @@ export function validPartyMon(
       !integer(mon.hp, 0, mon.stats[0])
     )
       return false;
-    // Stored stats must be the ones the game would calculate.
-    const stats = calcStats(data, mon.species, mon.dvs, mon.level, mon.statExp);
-    return stats.every((stat, index) => stat === mon.stats[index]);
+    // GiveExperiencePoints awards stat experience after every victory, but
+    // CalcMonStats only runs on a level-up (or a later PC recalculation).
+    // Preserve legitimate pending gains instead of silently applying them on
+    // load. Stored stats must stay inside the ROM-derived possible range.
+    const minimum = calcStats(data, mon.species, mon.dvs, mon.level);
+    const maximum = calcStats(data, mon.species, mon.dvs, mon.level, mon.statExp);
+    return mon.stats.every((stat, index) =>
+      stat >= minimum[index] && stat <= maximum[index]);
   } catch {
     return false;
   }

src/game/runtime.ts

@@ -21,6 +21,8 @@ export class NativeRuntime implements GameRuntime {
     private onUpdate: (world: GameWorld) => void,
     private onError: (error: unknown) => void,
     private player: () => { name: string; avatar: "chris" | "kris" },
+    /** Presentation handles menu navigation; battle rules stay in the world. */
+    private battleInput?: (button: Button) => boolean,
   ) {}
   async load(bytes: Uint8Array, canvas: HTMLCanvasElement) {
     this.dispose();
@@ -55,9 +57,14 @@ export class NativeRuntime implements GameRuntime {
     if (this.pressed.has(button) || !this.world) return;
     this.pressed.add(button);
     const world = this.world;
+    if (world.battle && this.battleInput?.(button)) {
+      this.publish();
+      return;
+    }
     if (button === "a") world.interact();
     if (button === "b") world.advanceDialogue();
-    if ((button === "up" || button === "down") && world.dialogue?.choice)
+    if ((button === "up" || button === "down") &&
+        (world.dialogue?.choice || world.battle?.prompt?.kind === "yesno"))
       world.moveCursor(button);
     if ((button === "start" || button === "select") && !world.busy)
       world.notice =

src/game/world/world.ts

@@ -143,7 +143,13 @@ interface ActiveScript {
   effect?: ScriptEffect;
   /** Committed save data for the whole interaction, used for mid-script saves. */
   committed: NativeSave;
-  rollback: { player: Actor; actors: Map<number, Actor>; spawned: Set<number> };
+  rollback: {
+    player: Actor;
+    actors: Map<number, Actor>;
+    spawned: Set<number>;
+    state: ScriptState;
+    mapId: string;
+  };
   waitTicks: number;
   moving: Map<number, { steps: MovementStep[]; index: number; wait: number }>;
   follow?: { leader: number; follower: number };
@@ -644,9 +650,13 @@ export class GameWorld {
 
   /** Evaluate map callbacks on a copy, so an unsupported callback leaves the
    * current map untouched. Methods follow the original map setup scripts. */
-  private prepareMap(id: string, method: "warp" | "connection" | "continue") {
+  private prepareMap(
+    id: string,
+    method: "warp" | "connection" | "continue",
+    sourceState = this.state,
+  ) {
     const map = this.assets.map(id);
-    const state = copyScriptState(this.state);
+    const state = copyScriptState(sourceState);
     const actors = new Map<number, Actor>();
     if (method !== "continue")
       for (let event = 0; event < 8; event++) state.events.delete(event);
@@ -779,6 +789,8 @@ export class GameWorld {
       ),
       committed,
       rollback: {
+        state: this.state,
+        mapId: this.mapId,
         player: copyActor(this.player),
         actors: new Map(
           [...this.actors].map(([id, actor]) => [id, copyActor(actor)]),
@@ -1045,10 +1057,12 @@ export class GameWorld {
 
   private finishScript() {
     const script = this.script!;
-    this.state = script.run.state;
     if (script.warp) {
       const { map, x, y } = script.warp;
-      const entry = this.prepareMap(map, "warp");
+      if (!this.assets.isPorted(map) || !this.walkable(this.assets.map(map), x, y))
+        throw new Error("Script warp destination is not supported.");
+      // Whiteout healing/money and destination callbacks commit together.
+      const entry = this.prepareMap(map, "warp", script.run.state);
       this.player = {
         ...this.player,
         x,
@@ -1057,7 +1071,7 @@ export class GameWorld {
         motion: undefined,
       };
       this.applyMap(entry);
-    }
+    } else this.state = script.run.state;
     this.script = undefined;
     this.dialogue = undefined;
     this.emote = undefined;
@@ -1071,6 +1085,8 @@ export class GameWorld {
     const script = this.script!;
     this.battle = undefined;
     this.battleRun = undefined;
+    this.state = script.rollback.state;
+    this.mapId = script.rollback.mapId;
     this.player = script.rollback.player;
     this.actors = script.rollback.actors;
     this.spawned = script.rollback.spawned;