Port timing/parity fixes, seamless battle transitions, faithful-res lock, and zoom-aware UI anchoring

Ports from a downstream fork, hand-surgered hunk-by-hunk to exclude the
fork's randomizer/pokescript work and to skip a FixedStep jitter-tolerance
attempt that never fixed the stutter it targeted.

- src/core/Timing.lua: hardware-accurate frame-delay catalog ported from
  pret/pokered, feeding BattleState:waitNext, EffectRegistry's miss/crit
  beats, TextBox/ChoiceBox scroll and prompt holds, and the battle
  silhouette slide/shake/blink/faint timings.
- Seamless battle transitions: Renderer:drawBattleWipe replaces the old
  160x144-only cascade with one wipe drawn over the whole surface at any
  zoom or window size; BattleTransition's per-style frame lengths are
  corrected against pokered-c's derivation; Transition.battleReturn adds
  the post-battle GBFadeInFromWhite the port never had.
- BATTLE SIZE / BATTLE BG options (BattleState:wantsFillScale/bgMode,
  Game.fillScaleInStack/worldBgBattleDim): battle surface can fill the
  window instead of the fixed integer letterbox, and the area around it
  can show white/black/the dimmed overworld instead of only white.
- src/core/FaithfulRes.lua: locks the window to an exact 160x144 multiple.
- Zoom-aware UI anchoring: Renderer:uiScale steps the UI down with survey
  zoom (gated to worldActive so the title/intro never shrink);
  Renderer:setUIAnchor lets TextBox, ChoiceBox, and an opted-in Menu
  (the START menu) pin themselves to a screen edge instead of the
  zoomed-out letterbox.

src/core/Timing.lua

@@ -0,0 +1,197 @@
+-- Hardware frame budgets, in fixed 60Hz logic steps.
+--
+-- The original spends a large share of its running time inside DelayFrames
+-- calls that produce no visible change -- the pause after a page break, the
+-- beat before a status move resolves, the one-HP-at-a-time drain of an HP
+-- bar.  Porting the visible half of a sequence and dropping the wait is what
+-- makes a port read as snappier than hardware, so every one of those waits
+-- lives here with its asm citation instead of as a file-local constant.
+--
+-- See docs/timing-parity.md for the full catalog and the measurement method;
+-- tools/scan_pokered_delays.ps1 regenerates the hardware side from a
+-- disassembly checkout.
+
+local Timing = {}
+
+-- home/palettes.asm:14 -- three frames to let the bg map fully update
+Timing.DELAY3 = 3
+
+-- home/fade.asm: each fade is a loop of `ld c, 8 / call DelayFrames`
+Timing.FADE_IN_FROM_BLACK  = 32 -- fade.asm:21, b = 4
+Timing.FADE_OUT_TO_BLACK   = 32 -- fade.asm:43, b = 4
+Timing.FADE_OUT_TO_WHITE   = 24 -- fade.asm:26, b = 3
+Timing.FADE_IN_FROM_WHITE  = 24 -- fade.asm:48, b = 3
+
+-- Overworld -----------------------------------------------------------------
+
+-- home/overworld.asm:703 PlayMapChangeSound tail-calls GBFadeOutToBlack on
+-- every map change.  There is no matching fade in: the new map is drawn while
+-- the palettes are still blacked out and LoadGBPal restores them in one write,
+-- so the map appears instantly.
+Timing.WARP_FADE_OUT = Timing.FADE_OUT_TO_BLACK
+Timing.WARP_FADE_IN  = 0
+
+-- home/overworld.asm:351-352 -- after a battle, before EnterMap
+Timing.POST_BATTLE_RETURN = 10
+
+-- engine/overworld/player_animations.asm:5-7 -- EnterMapAnim, the fly /
+-- teleport / dungeon-warp arrival: Delay3 then GBFadeInFromWhite
+Timing.SPECIAL_WARP_ENTRY = Timing.DELAY3 + Timing.FADE_IN_FROM_WHITE
+-- player_animations.asm:43 -- dungeon warp holds before handing back control
+Timing.DUNGEON_WARP_ARRIVAL = 50
+
+-- Text ----------------------------------------------------------------------
+
+-- home/text.asm:283-307 ScrollTextUpOneLine is `ld b, 5` of DelayFrame, and
+-- its own comment notes it is "always called twice in a row"
+Timing.TEXT_SCROLL_LINE = 5
+Timing.TEXT_SCROLL_PAIR = Timing.TEXT_SCROLL_LINE * 2
+
+-- Both _ContText (home/text.asm:262-277) and Paragraph (:230-243) print the
+-- â–¼ and call ProtectedDelay3 *before* ManualTextScroll starts watching the
+-- joypad, so three frames pass with the arrow up and the button ignored.
+Timing.TEXT_PRE_ADVANCE = Timing.DELAY3
+
+-- Paragraph / PageChar clear the box and then hold (home/text.asm:239-240,
+-- :254-255) before the next page starts typing.
+Timing.TEXT_PAGE_CLEAR = 20
+
+-- Totals, for the catalog and the parity tests.
+Timing.TEXT_CONT      = Timing.TEXT_PRE_ADVANCE + Timing.TEXT_SCROLL_PAIR
+Timing.TEXT_PARAGRAPH = Timing.TEXT_PRE_ADVANCE + Timing.TEXT_PAGE_CLEAR
+Timing.TEXT_PAGE      = Timing.TEXT_PARAGRAPH
+
+Timing.TEXT_PAUSE = 30 -- home/text.asm:500 TextCommand_PAUSE
+Timing.TEXT_DOT   = 10 -- home/text.asm:576 TextCommand_DOTS, per dot
+
+-- Menus ---------------------------------------------------------------------
+
+-- engine/menus/text_box.asm:322-323 / :333-334 -- both branches of a
+-- two-option (yes/no) menu hold before restoring the screen tiles
+Timing.YES_NO_ANSWER = 15
+
+Timing.LIST_MENU_OPEN   = 10             -- home/list_menu.asm:55-56
+Timing.LIST_MENU_REDRAW = Timing.DELAY3  -- home/list_menu.asm:64
+
+-- engine/menus/start_sub_menus.asm:224-225
+Timing.FIELD_TELEPORT = 60 + Timing.DELAY3
+
+-- Battle --------------------------------------------------------------------
+
+-- SlidePlayerAndEnemySilhouettesOnScreen (engine/battle/core.asm:9-49):
+-- the enemy comes in on BG SCX $90 -> $00 and the player's back pic on
+-- decrementing OAM x, both 2 px per frame -- so 144 px over 72 frames.  The
+-- port ran 160 px at 4 px/frame (40 frames), a little under twice too fast.
+Timing.BATTLE_SLIDE_IN_FRAMES = 72
+Timing.BATTLE_SLIDE_PX_PER_FRAME = 2
+
+-- PrintBeginningBattleText .trainerBattle (engine/battle/common_text.asm):
+-- SFX_SILPH_SCOPE plays into a clear window (PlaySound then
+-- WaitForSoundToFinish, which blocks), and only after `ld c, 20 /
+-- DelayFrames` do DrawAllPokeballs and the "wants to fight!" text run.
+Timing.TRAINER_INTRO_SFX_GAP = 20
+
+Timing.BATTLE_START_SENDOUT = 40 -- engine/battle/core.asm:155-156
+Timing.MOVE_ANIM_PRE        = Timing.DELAY3 -- core.asm:6638 PlayMoveAnimation
+
+-- core.asm:3185-3186 (player) / :5587-5588 (enemy).  Reached when the move
+-- has 0 BP (core.asm:3145 -- every status move) or missed (:3158), so this
+-- beat is paid on a large fraction of all turns.
+Timing.MOVE_STATUS_OR_MISS = 30
+
+-- PlayApplyingAttackAnimation's six types (AnimationTypePointerTable,
+-- engine/battle/animations.asm:490-524).  The two shake families are
+-- `AnimationShakeScreenHorizontallySlow`, whose double push/pop makes each
+-- outer pass cost 4b frames and run c times -- so c * 4b.
+Timing.SHAKE_VERTICAL     = 48 -- type 1, b=8: 8 x 6
+Timing.SHAKE_HORIZ_HEAVY  = 72 -- type 2, b=8: 8 x 9
+Timing.SHAKE_HORIZ_SLOW   = 48 -- type 3, lb bc, 6, 2: 2 x 4x6
+Timing.SHAKE_HORIZ_LIGHT  = 18 -- type 5, b=2: 2 x 9
+Timing.SHAKE_HORIZ_SLOW2  = 24 -- type 6, lb bc, 3, 2: 2 x 4x3
+
+-- Type 4 -- the player's damaging move with no added effect, and so the
+-- single most common animation in the game -- is AnimationBlinkMon
+-- (animations.asm:1360-1376): `ld c, 6` iterations of hide + DelayFrames 5
+-- + show + DelayFrames 5.  The asm's own comment calls it "a second or
+-- two"; the port ran it in 20 frames, three times too fast, which is a
+-- large part of why trading blows felt hurried.
+Timing.BLINK_MON = 60
+
+-- SlideDownFaintedMonPic (engine/battle/core.asm:1181-1222): b = PIC_HEIGHT
+-- (7) outer iterations, each closing with `ld c, 2 / call DelayFrames`.
+-- This one the port ran SLOWER than hardware, at 30.
+Timing.FAINT_SLIDE = 14
+
+Timing.RESIDUAL_TICK      = 20 -- core.asm:529-530 poison/burn/leech seed
+Timing.CRIT_OHKO_TEXT     = 20 -- core.asm:3813-3814
+Timing.SWITCH_PLAYER_MON  = 50 -- core.asm:2421-2422
+Timing.NO_MOVES_LEFT      = 60 -- core.asm:2753-2754
+Timing.TRAINER_VICTORY    = 40 -- core.asm:940-941
+Timing.PLAYER_BLACKOUT    = 40 -- core.asm:1143-1144
+Timing.FAINT_SLIDE_ROW    = 2  -- core.asm:1216-1217, per row
+Timing.TRAINER_SLIDE_COL  = 2  -- core.asm:1267-1268, per column
+
+-- HP bar (engine/gfx/hp_bar.asm) ---------------------------------------------
+--
+-- UpdateHPBar steps ONE HP point per loop iteration (:81-120).  Each
+-- iteration pays:
+--   * 1 frame in UpdateHPBar_PrintHPNumber's DelayFrame (:234) -- but only
+--     when wHPBarType is nonzero (:207-209), i.e. the player's own HUD and
+--     the party menu, never the enemy HUD; and
+--   * 2 frames per pixel the bar actually moved, from
+--     UpdateHPBar_AnimateHPBar's `ld c, 2 / call DelayFrames` (:147-148).
+-- The drain closes with one more pixel step and a Delay3 (:133-135).
+--
+-- So a player-side drain of D HP across P pixels costs D + 2P + 6 frames,
+-- while the same drain on the enemy HUD costs only 2P + 5.  A 150 HP mon
+-- losing everything takes 150 + 96 + 6 = 252 frames on hardware.
+
+Timing.HP_BAR_PIXELS      = 48 -- the bar is 48 px wide (GetHPBarLength)
+Timing.HP_BAR_PIXEL_STEP  = 2  -- frames per pixel of bar movement
+Timing.HP_BAR_HP_STEP     = 1  -- frames per HP point, player-side HUD only
+
+-- Pixels the bar shows for `hp` out of `maxHP`.  GetHPBarLength floors the
+-- 48ths and clamps the result to at least 1 for any nonzero HP
+-- (engine/gfx/hp_bar.asm:42-45); an empty bar is 0.
+function Timing.hpBarPixels(hp, maxHP)
+  if not maxHP or maxHP <= 0 then return 0 end
+  if hp <= 0 then return 0 end
+  local px = math.floor(hp * Timing.HP_BAR_PIXELS / maxHP)
+  if px < 1 then px = 1 end
+  return px
+end
+
+-- Frames one single-HP step of the drain costs: the per-HP number print
+-- (player side only) plus two frames for every pixel that step moved.
+function Timing.hpDrainStepFrames(fromHP, toHP, maxHP, playerSide)
+  local pixels = math.abs(Timing.hpBarPixels(toHP, maxHP)
+                          - Timing.hpBarPixels(fromHP, maxHP))
+  local frames = pixels * Timing.HP_BAR_PIXEL_STEP
+  if playerSide then frames = frames + Timing.HP_BAR_HP_STEP end
+  return frames
+end
+
+-- After the loop, .animateHPBarDone prints the number one last time, runs
+-- AnimateHPBar for a single pixel and falls into Delay3 (hp_bar.asm:132-135)
+-- -- so the tail costs 6 frames on the player's HUD and 5 on the enemy's.
+function Timing.hpDrainClosingFrames(playerSide)
+  local frames = Timing.HP_BAR_PIXEL_STEP + Timing.DELAY3
+  if playerSide then frames = frames + Timing.HP_BAR_HP_STEP end
+  return frames
+end
+
+-- Total cost of draining `fromHP` to `toHP`, for tests and for anything that
+-- needs to budget the whole animation up front.
+function Timing.hpDrainFrames(fromHP, toHP, maxHP, playerSide)
+  local total = 0
+  local hp = fromHP
+  local dir = (toHP < fromHP) and -1 or 1
+  while hp ~= toHP do
+    local nextHP = hp + dir
+    total = total + Timing.hpDrainStepFrames(hp, nextHP, maxHP, playerSide)
+    hp = nextHP
+  end
+  return total + Timing.hpDrainClosingFrames(playerSide)
+end
+
+return Timing