Finish the opening milestone's switching, items and acceptance run

- Decode evolution lists from the ROM; all 251 match the pinned PRET source.
- Compare CalcMonStats and CalcExpAtLevel against the original routines in
  the reference emulator.
- Add a continuous opening playthrough from the intro to the catching
  tutorial, reloading a JSON save after every stage.
- Port player switching in battle: the PKMN menu, forced choices after a
  faint, Shift mode's offer and double faints, with the original texts.
- Port HP and status healing items in battle through the ROM's ItemEffects,
  HealingHPAmounts and StatusHealingActions tables.
- Add the battle party menu and the Items pocket to the UI.

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

docs/NATIVE_PORT.md

@@ -32,7 +32,7 @@ These paths refer to the pinned [PRET source](https://github.com/pret/pokecrysta
 | Movement interpreter             | `macros/scripts/movement.asm`, `engine/overworld/movement.asm`, `engine/overworld/map_objects.asm`                             | Turns, steps, slides, jumps (two tiles with the original arc), sleeps, facing locks, visibility and emotes. `follow` takes one tile toward the leader's previous square. All movement opcodes decode, including teleport, fishing, skyfall, shake and flicker poses; Controlled reference scenes check spin, teleport, skyfall, fishing and flicker direction, visibility and lift.                                                              |
 | Specials                         | `data/events/special_pointers.asm`, `engine/rtc/timeset.asm`, `engine/overworld/decorations.asm`                               | Selected by routine address from the ROM table: `SetDayOfWeek`, initial DST flags, `RestartMapMusic` (no audio yet), room decoration toggles, `PokemonCenterPC` and `PlayersHousePC` (Bill's, the player's and Oak's PCs), the Town Map, `HealParty`, `HealMachineAnim` (presentation only), `CheckPokerus` and the `StubbedTrainerRankings_Healings` stub.                                                                              |
 | `game/scripts/pc.ts`             | `engine/events/pokecenter_pc.asm`, `engine/pokemon/bills_pc_top.asm`, `engine/pokemon/bills_pc.asm`, `engine/events/prof_oaks_pc.asm`, `engine/events/std_collision.asm` | The Pokémon Center and house PCs: Bill's PC (deposit, withdraw, release, change and name boxes), item storage, the empty mail box and Oak's rating. Menu strings and texts come from the ROM; lists are native. Moving Pokémon, the stats screen and printing are not ported. |
-| `game/rom/pokemon.ts`            | `data/pokemon/base_stats`, `evos_attacks.asm`, `data/moves/moves.asm`, `data/items/attributes.asm`, `engine/gfx/load_pics.asm` | Species, move and item names, base data, learnsets, move PP, item pockets, growth-rate exp and front pictures (`FixPicBank`, `PadFrontpic`). Starter pictures match rebuilt bytes.                                                      |
+| `game/rom/pokemon.ts`            | `data/pokemon/base_stats`, `evos_attacks.asm`, `data/moves/moves.asm`, `data/items/attributes.asm`, `engine/gfx/load_pics.asm` | Species, move and item names, base data, evolution lists, learnsets, move PP, item pockets, growth-rate exp and front pictures (`FixPicBank`, `PadFrontpic`). Starter pictures match rebuilt bytes; all 251 evolution lists match the pinned source. |
 | `game/party`                     | `engine/pokemon/move_mon.asm`, `engine/pokemon/caught_data.asm`, `engine/items/items.asm`                                      | `GeneratePartyMonStats` for script gifts: DVs, `FillMoves`, PP, exp, `CalcMonStatC`, happiness and caught data. `PutItemInPocket`, key items and `TossItem`. `SendMonIntoBox`, `SendGetMonIntoFromBox` (deposit and withdraw), `RestorePPOfDepositedPokemon` and `CalcLevel` for the PC's boxes and item storage. TMs and HMs are refused.                                         |
 | 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.                                                                      |
 
@@ -46,7 +46,7 @@ The opening scenes currently run end to end from the ROM: Mom's Pokégear, weekd
 
 `tests/reference-parity.spec.ts` loads the user's ROM into the reference emulator and places a small original test trampoline in emulated WRAM. It calls the ROM's `FarDecompress` routine at `$0b40`, then sets a return sentinel. Every output byte is compared with the native decoder for six supported map tilesets. This executes the original routine rather than comparing two copies of our code.
 
-The same suite compares 400 damage cases and 400 type-effectiveness cases per browser against the original battle routines. Battle unit tests cover win, escape, loss, experience, level-up and move-learning flows. This establishes parity only for the compared routines and inputs. It does not prove complete gameplay, rendering, battles, audio, timing or physical-device parity. Extend controlled comparisons as each subsystem is translated.
+The same suite compares 400 damage cases and 400 type-effectiveness cases per browser against the original battle routines, 300 `CalcMonStats` cases (with and without stat experience, including levels above 100 that reach the 999 cap) and every `CalcExpAtLevel` value for the six growth rates and levels 1–100. Battle unit tests cover win, escape, loss, experience, level-up and move-learning flows, and `tests/playthrough.test.ts` plays the whole opening quest from a new game through `GameWorld`'s inputs, with save/reload after each stage. This establishes parity only for the compared routines and inputs. It does not prove complete gameplay, rendering, battles, audio, timing or physical-device parity. Extend controlled comparisons as each subsystem is translated.
 
 ## Validation
 
@@ -80,7 +80,7 @@ Native saves are version 3. Version 2 added scene values by owning map, phone co
 
 `home/trainers.asm` and `engine/events/trainer_scripts.asm`: talking to an `OBJECTTYPE_TRAINER` object runs `TalkToTrainerScript` with the object's header copied as `wTempTrainer`; `_CheckTrainerBattle` runs `SeenByTrainerScript` with `wSeenTrainerDistance`. The world checks sight in `PlayerEvents` order: before warps, coordinate events and encounters at the end of a step (a seen player's tile events are then skipped, as `DisableEvents` does), and on idle ticks before scene scripts and input. Walls and objects do not block sight. `TrainerWalkToPlayer`/`ComputePathToWalkToPlayer` build the raw `wMovementBuffer` bytes, which `applymovementlasttalked` decodes with the normal movement reader. `wRunningTrainerBattleScript` lives in the script run: zero at the start, set by `loadmem` after the battle so `endifjustbattled` ends the after-script. Trainer commands without a map trainer are refused. `MomTriesToBuySomething` after scripted battles does nothing while Mom's savings (not ported) are zero.
 
-`engine/battle/core.asm` and `engine/battle/ai/items.asm`, `switch.asm`: when a trainer's Pokémon faints and others remain, `UpdateBattleStateAndExperienceAfterEnemyFaint` zeroes its party HP and runs `NewEnemyMonStatus`; `EnemyPartyMonEntrance` then sends out the Pokémon chosen by `FindMonInOTPartyToSwitchIntoBattle`. When every candidate is threatened it draws `BattleRandom & 7`, which tests pin. `AI_SwitchOrTryItem` runs before either side moves: `CheckAbleToSwitch`, the Often/Rarely/Sometimes thresholds, `AI_TrySwitch` and `AI_Switch` (withdraw text, HP and status back to the party). `CheckTypeMatchup` ignores the type its switch-AI callers load and uses `BATTLE_VARS_MOVE_TYPE`, so every such matchup uses the enemy's chosen move type; `FindEnemyMonsWithASuperEffectiveMove` never resets its result between Pokémon; `FindEnemyMonsWithAtLeastQuarterMaxHP` rotates HP bits instead of multiplying. All three bugs are kept. `UsedMoveText` records `wPlayerUsedMoves`. Refused: the Shift-mode offer to switch (`OfferSwitch`), `AskUseNextPokemon` with other Pokémon left, Pursuit on a switching Pokémon, Perish Song, Spikes, and trainer items. Side effects of the type scans on the move structs (overwritten types and animation) are not modelled; the next `ParseEnemyAction`/`ParsePlayerAction` reloads them.
+`engine/battle/core.asm` and `engine/battle/ai/items.asm`, `switch.asm`: when a trainer's Pokémon faints and others remain, `UpdateBattleStateAndExperienceAfterEnemyFaint` zeroes its party HP and runs `NewEnemyMonStatus`; `EnemyPartyMonEntrance` then sends out the Pokémon chosen by `FindMonInOTPartyToSwitchIntoBattle`. When every candidate is threatened it draws `BattleRandom & 7`, which tests pin. `AI_SwitchOrTryItem` runs before either side moves: `CheckAbleToSwitch`, the Often/Rarely/Sometimes thresholds, `AI_TrySwitch` and `AI_Switch` (withdraw text, HP and status back to the party). `CheckTypeMatchup` ignores the type its switch-AI callers load and uses `BATTLE_VARS_MOVE_TYPE`, so every such matchup uses the enemy's chosen move type; `FindEnemyMonsWithASuperEffectiveMove` never resets its result between Pokémon; `FindEnemyMonsWithAtLeastQuarterMaxHP` rotates HP bits instead of multiplying. All three bugs are kept. `UsedMoveText` records `wPlayerUsedMoves`. Refused: Pursuit on a switching Pokémon, Perish Song, Spikes, and trainer items. Side effects of the type scans on the move structs (overwritten types and animation) are not modelled; the next `ParseEnemyAction`/`ParsePlayerAction` reloads them.
 
 `BGEVENT_ITEM` runs `HiddenItemScript` with `wHiddenItemData`; `SetMemEvent` sets the item's flag.
 
@@ -147,7 +147,7 @@ Prompts continue on their own. The Dude's back picture, the ball animation,
 capture music and the Pokédex page (`NewPokedexEntry`) are not presented.
 `TX_LOW` text is now read as a line break.
 
-Refused: `SendMonIntoBox` (a catch with a full party), the other ball
+Refused: the other ball
 multipliers, Park/Safari Balls, a transformed target and a catch-rate
 division by zero. Pure vectors cover the catch formula; local-ROM tests
 cover capture, every break-free message, Master Ball draws, blank
@@ -155,3 +155,52 @@ nicknames, the blocked trainer ball, full-party rollback, both tutorial
 triggers, declining and the repeat offer, and mid-battle reloads. Browser
 tests cover PACK, catching and naming. No emulator comparison of the
 capture routines has been run.
+
+## Switching and healing items in battle
+
+`engine/battle/core.asm`: `BattleMenu_PKMN` and `TryPlayerSwitch` ("is
+already out", "can't be recalled" while wrapped or blocked by Mean Look,
+`CheckIfCurPartyMonIsFitToFight` with its fainted and Egg texts),
+`PlayerSwitch` and `BattleMonEntrance`. The switch runs `ParseEnemyAction`
+first, and `ParsePlayerAction` then skips it, so the random draws happen
+once. `SendOutMonText` and `WithdrawMonText` choose their cheer from the
+enemy's HP as a byte percentage of max HP / 4, including
+`wEnemyHPAtTimeOfPlayerSwitch`. A maximum HP below 4 would divide by zero
+and freeze the original; it is refused. `PursuitSwitch` reads the enemy
+move's effect as `GetMoveEffect` does, and Pursuit is refused.
+
+After a faint, `HandlePlayerMonFaint` runs `AskUseNextPokemon` (wild
+battles only; NO tries to run, compared with the first party Pokémon's
+stored Speed) and `ForcePlayerMonChoice`, whose party menu cannot be
+cancelled. A double faint in a trainer battle goes through `DoubleSwitch`,
+and a fainted Pokémon gains no share of the experience. When a trainer
+sends out the next Pokémon, `CheckWhetherToAskSwitch` and `OfferSwitch` run
+Shift mode's offer (the only battle style, since options are not ported);
+switching clears both participant sets as the original does.
+`NewBattleMonStatus` also clears the enemy's wrap count and Mean Look.
+
+`engine/items/item_effects.asm` and `pack.asm`: `BattlePack` shows the Items
+and Balls pockets. `CheckItemContext` gives Oak's "This isn't the time"
+text for items with no battle use. `ItemEffects` is read from the ROM:
+`RestoreHPEffect` (`ItemRestoreHP`, `HealingHPAmounts`, `RestoreHealth`) and
+`StatusHealingEffect` (`UseStatusHealer`, `StatusHealingActions`,
+`HealStatus`, `IsItemUsedOnConfusedMon`) run with `UseItem_SelectMon`, the
+party menu action texts and `UseDisposableItem`. "Won't have any effect"
+and a cancelled menu keep the item and the turn. `wItemEffectSucceeded`
+shares `wBattlePlayerAction`'s byte, so a used item takes the turn.
+`CalcPlayerStats` reapplies the paralysis and burn penalties to the side
+named by `hBattleTurn` after a switch of turns, which can be the enemy.
+Because `hBattleTurn` at the battle menu is not modelled everywhere, a
+status heal that would reapply a penalty to a paralysed or burned enemy is
+refused. Other item effects (X items, Poké Doll, Full Restore, revives,
+Ether) are refused.
+
+Tests: local-ROM battles cover switching, cancelling, the withdrawal texts,
+forced choices (including a fainted pick and a cancelled forced menu), run
+after NO, Shift mode's offer (accepted and declined), a trainer double
+faint, Potion, Max Potion, a Berry on a benched Pokémon, no-effect cases,
+Antidote and PSNCUREBERRY, Parlyz Heal restoring Speed, Oak's warning and a
+refused X Attack. Browser tests switch through the party menu and its
+SWITCH/STATS/CANCEL submenu and use a Potion from the Items pocket. The
+stats screen is not ported. No emulator comparison of these routines has
+been run.