Port field moves from the menu, SEL with Select, and moving Pokémon in Bill's PC

Field moves chosen in the party menu run their original checks and the
ROM's from-menu scripts (Cut, Surf, Strength, Flash, Whirlpool, Waterfall,
Sweet Scent), and Softboiled and Milk Drink share HP. SEL registers a key
item that Select then uses, replacing the Key Items shortcut, and Bill's
PC moves Pokémon between the party and every box.

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

tests/start-menu.test.ts

@@ -33,6 +33,7 @@ const BICYCLE = 7,
   LEFTOVERS = 0x92,
   FLOWER_MAIL = 0x9e,
   BERRY = 0xad;
+const SOFTBOILED = 0x87;
 const CUT = 0x0f,
   GUST = 0x10,
   SAND_ATTACK = 0x1c,
@@ -197,8 +198,11 @@ describe.skipIf(!existsSync(romPath))("the start menu", () => {
     pick(world, "CANCEL");
     pick(world, "PIDGEY");
     expect(menuItems(world)).toEqual(["CUT", "STATS", "SWITCH", "MOVE", "ITEM", "CANCEL"]);
-    pick(world, "CUT");
-    expect(world.notice).toBe("Using CUT from the menu is not ported yet.");
+    // CutFunction's CheckBadge, then the party menu again.
+    expect(pick(world, "CUT")).toEqual([
+      "Sorry! A new BADGE is required.",
+      "Choose a POKéMON.",
+    ]);
     // STATS shows the stats screen, and B returns to the party.
     pick(world, "PIDGEY");
     world.choose(menuItems(world).indexOf("STATS"));
@@ -209,6 +213,56 @@ describe.skipIf(!existsSync(romPath))("the start menu", () => {
     close(world);
   });
 
+  it("shares HP with Softboiled, which needs more than a fifth of it", () => {
+    const world = fixture();
+    const data = world.assets.pokemon;
+    const chansey = generatePartyMon(data, {
+      species: 113,
+      level: 20,
+      item: 0,
+      otId: world.playerId,
+      ot: "CHRIS",
+      dvs: 0x9abc,
+      caughtData: 0,
+    });
+    chansey.moves = [SOFTBOILED, 0, 0, 0];
+    world.state.party.push(chansey);
+    world.state.party[0].hp = 3;
+    const fifth = Math.floor(chansey.stats[0] / 5);
+    open(world);
+    pick(world, "POKéMON");
+    pick(world, "CHANSEY");
+    expect(pick(world, "SOFTBOILED")).toEqual(["Use on which POKéMON?"]);
+    // Not on itself, and not on a Pokémon at full HP.
+    expect(pick(world, "CHANSEY")).toEqual([
+      "That can't be used on this POKéMON.",
+      "Use on which POKéMON?",
+    ]);
+    expect(pick(world, "PIDGEY")[0]).toBe("That can't be used on this POKéMON.");
+    expect(pick(world, "CYNDAQUIL")).toEqual([
+      `CYNDAQUIL recovered ${Math.min(fifth, world.liveState.party[0].stats[0] - 3)}HP!`,
+      "Choose a POKéMON.",
+    ]);
+    // The cursor returns to the user.
+    const party = world.dialogue?.choice;
+    expect(party?.kind === "menu" && party.selected).toBe(2);
+    close(world);
+    expect(world.state.party[2].hp).toBe(chansey.stats[0] - fifth);
+    expect(world.state.party[0].hp).toBe(
+      Math.min(world.state.party[0].stats[0], 3 + fifth),
+    );
+
+    world.state.party[2].hp = fifth;
+    open(world);
+    pick(world, "POKéMON");
+    pick(world, "CHANSEY");
+    expect(pick(world, "SOFTBOILED")).toEqual([
+      "Not enough HP!",
+      "Choose a POKéMON.",
+    ]);
+    close(world);
+  });
+
   it("switches two Pokémon, and B cancels the move", () => {
     const world = fixture();
     open(world);
@@ -525,6 +579,49 @@ describe.skipIf(!existsSync(romPath))("the start menu", () => {
     expect(indoors.state.playerState).toBe(0);
   });
 
+  it("registers the Bicycle with SEL, and Select rides it without a message", () => {
+    const world = fixture();
+    // Nothing registered yet.
+    expect(world.useSelect()).toBe(true);
+    expect(until(world)).toEqual([
+      "An item in your PACK may be",
+      "registered for use on SELECT Button.",
+    ]);
+    close(world);
+    open(world);
+    pick(world, "PACK");
+    pickItem(world, BICYCLE);
+    expect(pick(world, "SEL")).toEqual(["Registered the BICYCLE."]);
+    close(world);
+    expect(world.state.registeredItem).toEqual({ which: 0x81, item: BICYCLE });
+    // The registration is saved.
+    world.restore(world.save());
+    expect(world.state.registeredItem).toEqual({ which: 0x81, item: BICYCLE });
+    expect(world.useSelect()).toBe(true);
+    expect(settle(world)).toEqual([]);
+    expect(world.diagnostic).toBe("");
+    expect(world.state.playerState).toBe(1);
+    expect(world.useSelect()).toBe(true);
+    expect(settle(world)).toEqual([]);
+    expect(world.state.playerState).toBe(0);
+
+    const indoors = fixture(PLAYERS_HOUSE, 7, 4);
+    indoors.state.registeredItem = { which: 0x81, item: BICYCLE };
+    indoors.useSelect();
+    expect(until(indoors)).toEqual(["OAK: CHRIS! This isn't the time to use that!"]);
+    close(indoors);
+    expect(indoors.state.playerState).toBe(0);
+  });
+
+  it("forgets a registered item that left its slot", () => {
+    const world = fixture();
+    world.state.registeredItem = { which: 0x02, item: POTION };
+    world.useSelect();
+    expect(until(world)[0]).toBe("An item in your PACK may be");
+    close(world);
+    expect(world.state.registeredItem).toEqual({ which: 0, item: 0 });
+  });
+
   it("offers no USE without a field menu, and a notice for unported effects", () => {
     const world = fixture();
     world.state.bag.items.push(