Port weather, copying moves, held items and obedience (#28)

Complete the weather, Substitute, Transform, called-move and forced-switch effects. Add held-item behavior, Exp. Share awards and badge-based traded Pokemon obedience, and persist trainer berry consumption.

Validated with 576 passing unit tests and 149 browser tests, native/reference builds, reference/vendor/release checks and 320 Metal Powder emulator comparisons per browser. Smart AI and special balls/battle types remain on #28.

tests/battle-fixture.ts

@@ -24,7 +24,9 @@ export function battleFixtureWorld(assets: CrystalAssets, scenario: BattleScenar
   mon.exp = 178; // One battle away from level 6 and Smokescreen.
   if (scenario === "loss") mon.hp = 1;
   if (scenario === "unsupported") {
-    mon.moves = [144, 0, 0, 0]; // Transform is explicitly refused.
+    // Psywave at level 1 loops forever in the original, so it stays refused.
+    mon.level = 1;
+    mon.moves = [149, 0, 0, 0];
     mon.pp = [10, 0, 0, 0];
   }
   world.state.party.push(mon);