Port evolution, Rare Candy, evolution stones and vitamins

Pokémon that levelled up evolve after a won battle, following
EvolveAfterBattle's checks over the ROM's evolution bytes, with the
evolution screen that B can stop and move learning outside battle. The pack
uses Rare Candy, stones (with ABLE/NOT ABLE labels) and vitamins, and its
pocket tabs now sit in their own row.

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

docs/PLAN.md

@@ -169,7 +169,16 @@ The numbered sections below keep their full scope. Each one opens with a checkli
 - PACK: the Items, Balls, Key and TM pockets (left and right change pockets; there are no TMs or HMs yet), and each item's submenu chosen by its permissions and field menu (`USE`, `GIVE`, `TOSS`, `SEL`, `QUIT`). TOSS asks how many and confirms. USE follows `UseItem`: Oak's warning without a field use, "You don't have a POKéMON!" for party items without one, and `_DoItemEffect` by the item's `ItemEffects` address: Potions and the other `HealingHPAmounts` items, status healers, Full Restore, Revive and Max Revive, the bitter Energypowder, Energy Root, Heal Powder and Revival Herb, Ethers, Elixers, the MysteryBerry and PP Up. The Bicycle closes the menu and runs `Script_GetOnBike` or `Script_GetOffBike` outdoors; elsewhere Oak objects, because `wFieldMoveSucceeded` shares `wItemEffectSucceeded`'s byte.
 - PP Up keeps a quirk: `wUsePPUp` shares `wTempPP`'s byte, so `ComputeMaxPP` adds one step (a fifth of the base PP, at most 7) to the current PP as well as the maximum. Sketch and moves with three PP Ups are "maxed out".
 - The menu runs on a script draft, like the PC. Changes commit when it closes; a save made while it is open keeps the state from before it. The start menu cursor, the party menu cursor and the last pocket stay in memory between openings and are cleared after a battle, as `CleanUpBattleRAM` does. The party cursor reaches the next battle's `ChangeHappiness`.
-- Select keeps opening the Key Items shortcut, standing in for a registered item. Not ported: field moves from the menu, MAIL, SEL (registering items), moving a Pokémon's moves to another party member with left and right, item reordering with Select, evolution stones, Rare Candy, vitamins and the other field items (each gives a notice and changes nothing).
+- Select keeps opening the Key Items shortcut, standing in for a registered item. Not ported: field moves from the menu, MAIL, SEL (registering items), moving a Pokémon's moves to another party member with left and right, item reordering with Select and the remaining field items such as Repel and Escape Rope (each gives a notice and changes nothing). Rare Candy, evolution stones and vitamins run since the evolution section below.
+
+## Implemented: evolution
+
+- `EvolveAfterBattle` runs after every won battle for the party members that levelled up (`wEvolvableFlags`, now recorded by the battle's experience routine), before the script resumes. Level, happiness (220 or more, by time of day) and Tyrogue's Attack/Defense evolutions follow the original checks, including the Everstone. The evolution data is walked byte by byte like the original, so a forced evolution skips a four-byte `EVOLVE_STAT` record the way the original does. Trades never evolve without Link mode.
+- The evolution screen shows "What? … is evolving!", then the old picture flashing into the new one on the original schedule (80 frames, then seven rounds of flashes). B stops it only during the waits between flashes, and never for a stone. A stopped evolution prints "Huh? … stopped evolving!" and skips that Pokémon's other entries.
+- After evolving: the species name replaces the nickname only if the nickname was the old species name, stats are recomputed with stat experience, HP rises by the maximum HP's increase, moves learned at exactly the current level are offered, and the Pokédex records the new species as seen and caught.
+- Learning a move outside battle follows `LearnMove`: an empty slot, or "delete an older move?", the choice of a move (HM moves can't be forgotten), "1, 2 and… Poof!", or "Stop learning …?" and "did not learn".
+- PACK: Rare Candy (`RareCandyEffect`: one level at the level's minimum experience; the HP gains the maximum HP's increase even for a fainted Pokémon; the caught-location happiness bonus; "grew to level", the stat box, new moves and a possible evolution), evolution stones (`EvoStoneEffect`: a forced `EvolvePokemon`; the party menu shows ABLE or NOT ABLE with the original's ten-byte, three-byte-step check; an Everstone or no matching evolution has no effect) and vitamins (`VitaminEffect`: ten more in the stat experience's high byte, up to 100, stats recomputed without changing the current HP, happiness).
+- Not presented: the evolution music, cries and the palette changes. Trade evolutions need Link.
 
 ## Native battles: current state
 
@@ -235,7 +244,7 @@ their scripts and story progression are supported.
 
 - [x] Native player, party, Pokémon, bag, money and quest models with versioned saves
 - [x] Typed ROM decoders for species, moves, growth rates, items, encounters and trainers
-- [x] Decoder for evolutions (the evolution itself is not ported yet)
+- [x] Decoder for evolutions, and evolution after battles and from items (see section 3)
 - [x] Mom, Elm's introduction, the starter, naming and the aide's Potion
 - [x] Route 29, Cherrygrove City, the Poké Mart and the Pokémon Center
 - [x] Route 30's trainers, Mr. Pokémon's house, the Mystery Egg and the Pokédex
@@ -253,7 +262,7 @@ Introduce native player, party, Pokémon, inventory, money and quest models. Rea
 
 Expand script calls, choices, scene state, inventory commands and native special handlers. Translate routines reached through assembly calls into explicit native services; never fall back to emulator execution in the shipping game.
 
-Meeting Mom, Elm's introduction, the starter, the aide's Potion, Route 29, Cherrygrove, Route 30's trainers, Mr. Pokémon's house, the Cherrygrove rival battle, the return to Elm, capture, the catching tutorial, the PC, the introduction's naming and clock screens, and switching and healing items in battle run now. The opening milestone is complete within the recorded acceptance boundaries. The start menu, party menu and pack now run outside battle. Next: evolution, then MOVE PKMN W/O MAIL.
+Meeting Mom, Elm's introduction, the starter, the aide's Potion, Route 29, Cherrygrove, Route 30's trainers, Mr. Pokémon's house, the Cherrygrove rival battle, the return to Elm, capture, the catching tutorial, the PC, the introduction's naming and clock screens, and switching and healing items in battle run now. The opening milestone is complete within the recorded acceptance boundaries. The start menu, party menu and pack now run outside battle, and Pokémon evolve. Next: MOVE PKMN W/O MAIL, SEL and field moves from the menu, then the Pokégear.
 
 Complete and validate the native battle engine: deterministic randomness, stats, move selection, accuracy/critical checks, damage, status, turn order, switching, fainting, experience, capture and rewards. Compare controlled seeds and states with the original, including integer rounding and overflow behavior.
 
@@ -263,7 +272,8 @@ Acceptance: finish the opening quest, including encounters and the rival battle,
 
 - [x] Pokémon Center healing, standard Poké Marts and Reflect/Light Screen
 - [ ] Remaining battle commands, move and item effects, AI layers and special battles
-- [ ] Evolution, breeding, happiness, eggs and PC storage
+- [x] Evolution by level, happiness, Tyrogue's stats and stones, with Rare Candy and vitamins (trade evolutions need Link)
+- [ ] Breeding, eggs and the rest of PC storage
 - [ ] Field moves, gyms, Rocket events, the phone and Pokégear, puzzles, minigames, daily events, roaming Pokémon and the postgame
 - [ ] Johto beyond Route 30, the League, Kanto and the final battle
 - [ ] Music and sound through Web Audio