Open the Battle Tower and add the badges' type boosts (Closes #32)

The Route 40 gate, the Battle Tower and its rooms are open with the
offline challenge: the rules, the save before entering, the level menu
with its level and uber checks, seven trainers drawn from
BattleTowerTrainers with Pokémon from BattleTowerMons, BattleTowerText,
save and quit with the receptionist resuming it, cancelling, losing and
the vitamin reward. After each battle the party and Pokédex return to the
quick save's, as LoadPokemonData does.

Battle Tower battles turn off obedience, badge boosts, experience, items,
AI items and prize money, use Falkner's AI attributes, keep Sleep to one
to three turns and never fail the AI's status moves at random. New script
command battletowertext; new specials BattleTowerAction (offline actions),
BattleTowerRoomMenu, CheckForBattleTowerRules, BattleTowerBattle,
LoadOpponentTrainerAndPokemonWithOTSprite, Menu_ChallengeExplanationCancel,
TryQuickSave and Reset.

DoBadgeTypeBoosts was missing from every battle; it now adds an eighth of
the damage for the first badge matching the move's type on the player's
turn, checked against the original routine.

This completes Johto from Azalea to Blackthorn: Kanto, the League and the
S.S. Aqua continue on #33; radio, rematches and Buena's password on #30.

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

docs/NATIVE_PORT.md

@@ -54,6 +54,7 @@ These paths refer to the pinned [PRET source](https://github.com/pret/pokecrysta
 | `game/scripts/lake-of-rage.ts`, Route 42 to Mahogany, the Lake of Rage, the Rocket Hideout and Pryce | `engine/events/magikarp.asm` (`CheckMagikarpLength`, `CalcMagikarpLength`, `PrintMagikarpLength`, `MagikarpHouseSign`), `engine/menus/intro_menu.asm` (`InitializeMagikarpHouse`), `engine/pokemon/search_party.asm` (`FindThatSpecies`), `engine/overworld/scripting.asm` (`DoScene`), `engine/events/money.asm` (`TakeMoney`) | The Magikarp is measured from its own DVs and OT ID with the battle code's `CalcMagikarpLength` (whose `.BCLessThanDE` compares only the high byte). A longer one, compared feet then inches, becomes the record with the Magikarp's OT name as holder; the record starts at 3′6″ by RALPH and is saved as `magikarpRecord`. `FindThatSpecies` reads `wPartySpecies`, where an Egg is EGG, so an Egg is never found. `setmapscene`/`setscene` on a map without a scene variable (Route 43, the Lake of Rage): `GetMapSceneID` leaves `de` alone and `DoScene` still writes the byte through it when it is nonzero. At the Route 43 gate `de` is `EventFlagAction`'s byte offset of `EVENT_CLEARED_ROCKET_HIDEOUT` (4), the MBC3 RAM-enable register, so nothing changes. After the Red Gyarados, `de` is whatever `closetext` left; the port consumes the byte and changes nothing, and that write was not checked in an emulator. `TakeMoney` leaves a short account at zero, so the Route 43 Rockets take all of a smaller balance. The Rocket Hideout's cameras, traps, passwords, executives and Electrodes and Pryce's ice floor run on ported primitives; `PlayCurMonCry` is audio. `tests/mahogany.test.ts` and five playthrough stages cover them. |
 | `game/scripts/blackthorn.ts`, the Radio Tower takeover, Ice Path, Blackthorn and Dragon's Den | `engine/events/dratini.asm` (`GiveDratini`), `engine/events/move_deleter.asm` (`MoveDeletion`), `engine/pokemon/mon_menu.asm` (`ChooseMoveToDelete`), `engine/events/whiteout.asm` (`Script_Whiteout`), `data/maps/setup_scripts.asm` (`MapSetupScript_Continue`) | `GiveDratini` searches the party backwards by species and writes `.Movesets` 0 (WRAP, THUNDER WAVE, TWISTER, EXTREMESPEED) or 1 with each move's base PP; a value of 2 or more changes nothing. `MoveDeletion` follows the routine's order of questions; `ChooseMoveToDelete` is shown as a list of the moves, and `.DeleteMove` shifts the later moves and PP bytes, PP Ups included. A save records objects whose visibility no longer matches their flags: `MapSetupScript_Continue` skips `LoadMapObjects`, so a flagless object a script made disappear (the Radio Tower director) stays gone after Continue and one that appeared with its flag set stays visible; a later visit rebuilds them from the map. A battle lost inside an `scall` jumps to `Script_Whiteout` without unwinding; its `newloadmap` is followed by `endall`, which drops the caller. The switch room's doors, the warehouse's reset, the Ice Path and Blackthorn Gym stone tables, whirlpools and the Dragon Shrine quiz run on ported primitives. `tests/blackthorn.test.ts`, `tests/radio-tower.test.ts` and six playthrough stages cover them. |
 | `game/scripts/tin-tower.ts`, Tin Tower and Whirl Islands | `engine/pokemon/search_owned.asm` (`BeastsCheck`, `MonCheck`, `CheckOwnMonAnywhere`, `CheckOwnMon`) | `CheckOwnMonAnywhere` returns nothing with an empty party, then reads the party structs' species (an Egg counts as its species), `sBox` and the fourteen `sBoxN` copies, matching the player's ID and the OT's first five letters (`NAME_LENGTH_JAPANESE - 2` compares, stopping early at a shared terminator); the Day-Care is not searched. The original's `sBox` is the current box, and its own `sBoxN` slot may still hold an older copy from before the last box change; the port keeps the boxes without stale copies, so a Pokémon only in such a copy is not found. The sages, Suicune, Ho-Oh and Lugia run on ported primitives (`BATTLETYPE_SUICUNE`, `BATTLETYPE_FORCEITEM`). `tests/tin-tower.test.ts` and two playthrough stages cover them. |
+| `game/scripts/battle-tower.ts`, the Battle Tower | `engine/events/battle_tower/battle_tower.asm` (`BattleTowerAction`, `RunBattleTowerTrainer`, `ReadBTTrainerParty`, `CopyBTTrainer_FromBT_OT_TowBT_OTTemp`, `BattleTower_GiveReward`, `BattleTower_RandomlyChooseReward`, `LoadOpponentTrainerAndPokemonWithOTSprite`, `CheckForBattleTowerRules`), `engine/events/battle_tower/load_trainer.asm`, `engine/events/battle_tower/rules.asm`, `engine/events/battle_tower/trainer_text.asm`, `mobile/mobile_46.asm` (`_BattleTowerRoomMenu`, `BattleTower_LevelCheck`, `BattleTower_UbersCheck`), `mobile/mobile_5f.asm` (`Menu_ChallengeExplanationCancel`), `engine/link/link.asm` (`TryQuickSave`), `engine/battle/core.asm`, `engine/battle/effect_commands.asm`, `engine/battle/misc.asm` (`DoBadgeTypeBoosts`) | The Battle Tower's SRAM and the work RAM its scripts share are saved as `battleTower`. The trainer sampler keeps its index as the running byte after a repeated trainer; the Pokémon sampler starts again from `hRandomAdd`; both fold `Random`'s `hRandomAdd` into a byte below a power-of-two mask, which the port draws from its random source. `BattleTowerText` reads the class's gender (1.1 behaviour) and picks the greeting from `hRandomAdd` (0-24 male, 0-14 female), keeping it for the end texts. Each battle start counts the battle and marks the challenge in progress, as `CopyBTTrainer_FromBT_OT_TowBT_OTTemp` does; `LoadPokemonData` then returns the party, Pokédex and Unown Dex to the quick save's. The level menu shows the levels as a list; its CANCEL/B question and the mobile code's YES/NO flow are modelled from their outcomes (YES leaves with $a, NO picks a level again). `TryQuickSave` asks the overwrite question for the player's own save and shows the saving texts; the port keeps the place and Pokémon data `LoadPokemonData` and `Reset` return to. The native game saves itself, so the original's "left without saving" state (a reset during a challenge) cannot arise: a reload replays the room's script. `Reset` returns the player to the quick save's place with the 1F scene set to check the challenge; the original's rollback of money gained by Pay Day is not reproduced. In battle, `wInBattleTowerBattle` turns off obedience, `DoBadgeTypeBoosts`, `BadgeStatBoosts`, experience, the pack (BattleMenu_Pack says items can't be used), AI items and prize money, uses Falkner's AI attributes, keeps Sleep to `%011` and skips the AI's random failure for Sleep, Poison, stat-lowering and Paralyze moves; a loss shows BattleTowerText and does not white out. `DoBadgeTypeBoosts` was added to every battle (it was missing). BATTLETOWERACTION_LEVEL_CHECK and _UBERS_CHECK and the mobile actions are reached only from unreferenced scripts and stay refused. `tests/battle-tower.test.ts`, `tests/battle-tower-engine.test.ts` and `tests/reference-badges.spec.ts` cover them. |
 | `game/scripts/slot-machine.ts`, `game/scripts/card-flip.ts` | `engine/games/slot_machine.asm`, `engine/games/card_flip.asm`, `engine/gfx/cgb_layouts.asm` | Both on a realtime tile screen (two frames per tick, buffered buttons). Slots: reel strips, spin rates and scrolling, bias tables with the lucky machine and seven streak, reel 3's Golem and Chansey replay with their sprites, payouts. Card Flip: deck, 12×11 board, cursor sprites and `ChooseCard_HandleJoypad`, paytable. Tilemaps, all 48 cursor positions, selected reel states and whole Golem/Chansey/Egg sequences are checked against the ROM (`tests/reference-game-corner.spec.ts`, which runs `CardFlip_UpdateCursorOAM`, `Slots_UpdateReelPositionAndOAM`/`.SpinReel` and the sprite-animation engine's own Golem/Chansey/Egg routines): the cursor, the reel symbols and the three creatures each anchor an OAM-relative pixel pair 8 (x) and 16 (y) beyond the screen's, as `cursorSprites` reads; `depixel`'s own two arguments end up swapped by `_InitSpriteAnimStruct` (confirmed against the reference emulator), so Golem/Chansey/Egg's X and Y bases were swapped to match, and Golem's own OAM table X-flips its right half. `PlaySpriteAnimations` is compared frame by frame over a three-Golem run and a Chansey round with two eggs (shadow OAM, `wSlotsDelay` and `hSCY`): frames last 8 ticks (the first draw plus 7 decrements); Golem's frames 3 and 4 flip the whole OAM set (offsets become −8−offset); a sprite removed by `DeinitializeSprite` is still drawn that tick, because `UpdateAnimFrame` runs after the animation function; the Golem's roll toggles `hSCY` by ±2, which the tile screen shows with the space tiles `_SlotMachine` filled the BG map with. The rows scrolled in use palette 0, since the attribute map beyond row 18 is not reproduced. No sound. |
 | Text interpreter                 | `macros/scripts/text.asm`, `constants/charmap.asm`, `home/text.asm`                                                            | Literal/far text, RAM names and string buffers from native state, numbers of dots, and sound or pause cues (consumed). `text_asm` and other RAM reads are refused.                                                                      |
 

docs/PLAN.md

@@ -22,6 +22,7 @@ The emulator-backed prototype is now at `/reference.html`. The default applicati
 | Route 42 to Mahogany, the Lake of Rage, the Rocket Hideout and Pryce          | Done                                    |
 | The Radio Tower takeover, Ice Path, Blackthorn, Clair and Dragon's Den       | Done                                    |
 | Tin Tower, Suicune, Ho-Oh, Whirl Islands and Lugia                           | Done                                    |
+| The Battle Tower                                                             | Done                                    |
 | Wild and trainer battles, capture and the catching tutorial                  | Done for the areas that are open        |
 | 1. Complete the overworld foundation                                         | Done                                    |
 | 2. Opening story and first battle slice                                      | Mostly done                             |
@@ -446,7 +447,16 @@ The numbered sections below keep their full scope. Each one opens with a checkli
 - Tin Tower's nine floors and roof and the Whirl Islands' eight maps are open. The Clear Bell lets the player past the entrance's sages and through the Wise Trio's room; in Tin Tower 1F Raikou and Entei flee unless caught, and Suicune battles (`BATTLETYPE_SUICUNE`), followed by Eusine.
 - New specials (`game/scripts/tin-tower.ts`): `MonCheck` and `BeastsCheck` over `CheckOwnMonAnywhere`: the party and every box, the player's ID and the first five letters of the OT, an empty party finding nothing, the Day-Care left out. After the League with all three beasts, the second Wise Trio appears and gives the Rainbow Wing; its stairs lead up to Ho-Oh on the roof. Lugia waits at the bottom of the Whirl Islands for a player with the Silver Wing. Both battles use `BATTLETYPE_FORCEITEM`.
 - The playthrough driver plans ledge jumps (for the later stages only, so the earlier seeded stages keep their recorded paths), waterfalls carrying a surfer down, warp panels landing elsewhere on a map, and Surf and Whirlpool between warps in `travel`. Tests: `tests/tin-tower.test.ts` (MonCheck's rules, the Rainbow Wing and the climb to Ho-Oh, the Whirl Islands to Lugia). The playthrough continues for two more stages: Routes 45 and 46 back to Ecruteak, and Tin Tower's Suicune.
-- Remaining: the Battle Tower, Olivine's port and the S.S. Aqua (board #33), radio and rematches (#30), breeding (#29), mobile and link features, and audio. `CheckOwnMonAnywhere` in the original also reads the current box's own SRAM copy, which can be stale; the port keeps no stale copy.
+- Remaining: the Battle Tower (increment H below), Olivine's port and the S.S. Aqua (board #33), radio and rematches (#30), breeding (#29), mobile and link features, and audio. `CheckOwnMonAnywhere` in the original also reads the current box's own SRAM copy, which can be stale; the port keeps no stale copy.
+
+## Implemented: the Battle Tower (board #32, increment H)
+
+- The Route 40 gate, the Battle Tower outside and its 1F, elevator, hallway and Battle Room are open. Offline challenges work as in the original: the explanation, the Challenge/Explanation/Cancel menu, the party rules (three Pokémon, different species and items, no Egg), the save before entering, the level menu (L:10-L:40, or to L:100 after the Hall of Fame) with its level and uber checks, the walk to the room, seven trainers with healing and "next opponent" questions, save and quit, cancelling, a loss, and the reward of five of a random vitamin (not Lucky Punch).
+- New in `game/scripts/battle-tower.ts`: `BattleTowerAction`'s offline actions on a saved `battleTower` state (the challenge state, streak count and trainers, the last two trainers' species, the level group, the reward and the file flags); `LoadOpponentTrainerAndPokemon`'s trainer and Pokémon sampling (no repeated trainer, species or item, none of the last two trainers' species) from `BattleTowerTrainers` and `BattleTowerMons`; `BattleTowerText` (a random greeting, kept for the end texts); `_CheckForBattleTowerRules`; `Menu_ChallengeExplanationCancel`; the level menu of `_BattleTowerRoomMenu`; `TryQuickSave`; and `Reset`. New script command: `battletowertext`. The opponent's overworld sprite comes from `BTTrainerClassSprites`.
+- Battle Tower battles (`battleTower` in the battle engine): the SET style, no obedience check, badge boosts, experience, items or prize, no AI item use, Falkner's AI attributes, Sleep of one to three turns, no random failure of the AI's status moves, and BattleTowerText instead of the prize or a whiteout. After each battle `LoadPokemonData` returns the party and Pokédex to the quick save's, so held items used in battle come back.
+- `DoBadgeTypeBoosts` was missing from all battles: on the player's turn, the first badge whose type is the move's adds an eighth of the damage. `tests/reference-badges.spec.ts` now compares it with the original routine for every Johto badge byte, Kanto badges, types, damage values, both turns and the Battle Tower.
+- The native game saves itself, so a reload during a challenge replays the room's script from its start instead of reaching the original's "left without saving" state, and `Reset` (save and quit) returns to where the quick save was made. The original also rolls back money gained by Pay Day there; the port keeps it.
+- Tests: `tests/battle-tower.test.ts` (the gate, every rule's text, the level and uber checks, the L:40 menu, a full streak and its reward, save and quit and the resume, a saved-and-left state after a reload, cancelling and losing) and `tests/battle-tower-engine.test.ts` (no experience, prize or items; obedience; a loss without a whiteout).
 
 ## Native battles: current state