Port the Pokégear, phone calls and Mom's bank

POKéGEAR in the start menu runs the clock, Town Map and phone cards with
the original joypad rules. Calls to Elm and Mom run their callee scripts,
with the out-of-area and out-of-hours cases and HangUp's corrected timing.
Mom saves a quarter of trainer prizes once asked, talking to her at home
opens BankOfMom (GET, SAVE, CHANGE and the DST checks) with its digit
amount box, and MomTriesToBuySomething buys items and dolls with her
savings. Saves gain Mom's money, her next item and its trigger balance.

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

src/game/scripts/start-menu.ts

@@ -14,8 +14,10 @@ import {
   copyScriptState,
   type MartEntry,
   type ScriptEffect,
+  type ScriptHost,
   type ScriptState,
 } from "./interpreter";
+import { Pokegear } from "./pokegear";
 import { readString, readText, type TextContext } from "./text";
 
 type Input = number | string | undefined;
@@ -109,6 +111,10 @@ export interface StartMenuHost {
   landmark(): number;
   /** A field move's checks for party slot `mon`, on the menu's draft. */
   fieldMove(state: ScriptState, mon: number, move: number): MenuFieldMove;
+  /** The script host a Pokégear phone call runs with. */
+  scriptHost(): ScriptHost;
+  /** GetWorldMapLocation for any map. */
+  landmarkOf(mapId: string): number;
 }
 
 /** The overworld start menu (engine/menus/start_menu.asm) with its
@@ -282,6 +288,16 @@ export class StartMenuRun {
         case STARTMENUITEM_PACK:
           if (yield* this.pack()) return;
           break;
+        case STARTMENUITEM_POKEGEAR:
+          // StartMenu_Pokegear returns to the start menu.
+          yield* new Pokegear(this.state, {
+            reader: this.reader,
+            data: this.data,
+            text: () => this.text(),
+            scriptHost: () => this.host.scriptHost(),
+            landmarkOf: (mapId) => this.host.landmarkOf(mapId),
+          }).run();
+          break;
         case STARTMENUITEM_EXIT:
           return;
         case STARTMENUITEM_SAVE: