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;
   }