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/main.ts

@@ -230,12 +230,13 @@ function nameField(
 }
 type MartChoice = Extract<
   Choice,
-  { kind: "martmenu" | "martlist" | "martquantity" }
+  { kind: "martmenu" | "martlist" | "martquantity" | "pack" }
 >;
 function martChoice(choice: Choice): MartChoice | undefined {
   return choice.kind === "martmenu" ||
     choice.kind === "martlist" ||
-    choice.kind === "martquantity"
+    choice.kind === "martquantity" ||
+    choice.kind === "pack"
     ? choice
     : undefined;
 }
@@ -248,13 +249,18 @@ function showMart(world: GameWorld, mart: MartChoice | undefined) {
     martMenuKey = "";
     return;
   }
-  // The PC's item storage reuses these lists without prices.
+  // The PC's item storage and the pack reuse these lists without prices.
   const shop =
-    mart.kind === "martmenu" || mart.mode === "buy" || mart.mode === "sell";
-  get("mart").setAttribute("aria-label", shop ? "Poké Mart" : "Item storage");
+    mart.kind === "martmenu" ||
+    (mart.kind !== "pack" && (mart.mode === "buy" || mart.mode === "sell"));
+  get("mart").setAttribute(
+    "aria-label",
+    shop ? "Poké Mart" : mart.kind === "pack" ? "Pack" : "Item storage",
+  );
   get("mart-money").hidden = !shop;
   get("mart-money").textContent = `MONEY ¥${world.liveState.money}`;
-  get("mart-prompt").textContent = mart.kind === "martlist" ? "" : mart.prompt;
+  get("mart-prompt").textContent =
+    mart.kind === "martlist" || mart.kind === "pack" ? "" : mart.prompt;
   const key = JSON.stringify(mart);
   if (key === martMenuKey) return;
   martMenuKey = key;
@@ -291,6 +297,40 @@ function showMart(world: GameWorld, mart: MartChoice | undefined) {
     );
     return;
   }
+  if (mart.kind === "pack") {
+    // Pocket tabs (left and right on the keyboard), then the pocket's items.
+    const tabs = mart.pockets.map((pocket, index) => {
+      const tab = button(pocket.name, () => {
+        const world = runtime.world;
+        const choice = world?.dialogue?.choice;
+        if (choice?.kind !== "pack" || !world) return;
+        choice.pocket = index;
+        choice.selected = 0;
+        showWorld(world);
+      });
+      tab.setAttribute("aria-pressed", String(mart.pocket === index));
+      return tab;
+    });
+    const entries = mart.pockets[mart.pocket].entries;
+    const buttons = entries.map((entry, index) =>
+      button(
+        entry.name,
+        () => runtime.choosePackEntry(mart.pocket, index),
+        {
+          detail: entry.owned === undefined ? undefined : `×${entry.owned}`,
+          selected: mart.selected === index,
+        },
+      ),
+    );
+    if (!entries.length) {
+      const empty = button("Empty", () => {}, { wide: true });
+      empty.disabled = true;
+      buttons.push(empty);
+    }
+    buttons.push(button("BACK", () => runtime.choose(-1), { wide: true }));
+    menu.replaceChildren(...tabs, ...buttons);
+    return;
+  }
   if (mart.kind === "martlist") {
     const buttons = mart.entries.map((entry, index) =>
       button(entry.name, () => runtime.choose(index), {
@@ -433,7 +473,13 @@ function showFieldMenu(world: GameWorld) {
 function handleFieldInput(button: Button): boolean {
   const world = runtime.world;
   if (!world || world.battle) return false;
-  if ((button === "start" || button === "select") && !world.busy) {
+  // Start opens the start menu; Select, standing in for a registered
+  // item, opens the Key Items shortcut.
+  if (button === "start" && !runtime.fieldMenuOpen && !world.busy) {
+    runtime.openStartMenu();
+    return true;
+  }
+  if (button === "select" && !world.busy) {
     runtime.fieldMenuOpen = !runtime.fieldMenuOpen;
     fieldCursor = 0;
     return true;