Port the start menu, the party menu and the pack outside battle

Start opens the original start menu. POKéMON shows the party with the
Pokémon submenu (stats, switching, move order, held items); PACK shows the
four pockets with the field item effects for healing, PP and the Bicycle,
plus giving and tossing. The menu runs on a script draft, and its cursors
persist until a battle clears them. Select keeps the Key Items shortcut.

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

src/game/rom/pokemon.ts

@@ -170,6 +170,20 @@ export class PokemonData {
     );
     return Boolean(permissions & 0x80);
   }
+  /** ItemAttributes permissions, bit 6 (CANT_SELECT_F): CheckSelectableItem. */
+  itemUnselectable(item: number): boolean {
+    this.checkItem(item);
+    const permissions = this.reader.byte(
+      SYMBOLS.itemAttributes + (item - 1) * 7 + 4,
+    );
+    return Boolean(permissions & 0x40);
+  }
+  /** CheckItemMenu: the field menu (ITEMMENU_*), the help byte's high
+   * nibble. CheckItemContext reads the low one in battle. */
+  itemFieldMenu(item: number): number {
+    this.checkItem(item);
+    return this.reader.byte(SYMBOLS.itemAttributes + (item - 1) * 7 + 6) >> 4;
+  }
   pocketName(pocket: Pocket): string {
     const r = this.reader,
       bank = r.bank(SYMBOLS.itemPocketNames);

src/game/rom/profile.ts

@@ -173,6 +173,7 @@ export const EVENTS = {
 
 /** Engine flag indices named directly by translated routines. */
 export const ENGINE_FLAGS = {
+  pokegear: 4,
   pokedex: 11,
   allFruitTrees: 84,
 } as const;
@@ -404,6 +405,42 @@ export const PC = {
   Script_ReceivePhoneCall: 0x90241,
 } as const;
 
+/** The start menu, the party menu and its Pokémon submenu, and the pack
+ * outside battle: menu data, strings and texts, keyed by their PRET labels
+ * so that \`npm run check:reference\` can verify each address by name. */
+export const MENU = {
+  "StartMenu.Items": 0x126eb,
+  PartyMenuStrings: 0x504d2,
+  MonMenuOptionStrings: 0x24caf,
+  MonMenuOptions: 0x24cd9,
+  "GiveTakeItemMenuData.Items": 0x12ca3,
+  String_MoveWhere: 0x1316b,
+  MailItems: 0xb9e80,
+  PokemonSwapItemText: 0x12caf,
+  PokemonHoldItemText: 0x12cb4,
+  PokemonRemoveMailText: 0x12cb9,
+  PokemonNotHoldingText: 0x12cbe,
+  ItemStorageFullText: 0x12cc3,
+  PokemonTookItemText: 0x12cc8,
+  PokemonAskSwapItemText: 0x12ccd,
+  ItemCantHeldText: 0x12cd2,
+  "GiveItem.AnEggCantHoldAnItemText": 0x1048d,
+  "MenuHeader_UsableKeyItem.MenuData": 0x10251,
+  "MenuHeader_UsableItem.MenuData": 0x1027c,
+  "MenuHeader_UnusableItem.MenuData": 0x102a1,
+  "MenuHeader_UnusableKeyItem.MenuData": 0x102b8,
+  "MenuHeader_HoldableKeyItem.MenuData": 0x102d5,
+  "MenuHeader_HoldableItem.MenuData": 0x102fa,
+  AskThrowAwayText: 0x10ae4,
+  AskQuantityThrowAwayText: 0x10ae9,
+  ThrewAwayText: 0x10aee,
+  YouDontHaveAMonText: 0x10af8,
+  RaiseThePPOfWhichMoveText: 0xf725,
+  PPIsMaxedOutText: 0xf72f,
+  PPsIncreasedText: 0xf734,
+  BicycleEffect: 0xee08,
+} as const;
+
 /** Battle engine tables and texts, keyed by their PRET labels so that
  * \`npm run check:reference\` can verify each address by name. */
 export const BATTLE = {