Four-stage keyer in flood_key_magenta: unchanged border flood, strict
interior-pocket key, is_magenta fringe erosion, and despill; hd_assets
inherits it via import. New --reprocess mode re-keys assets/raw sources
without API calls (skips tiles, rebuilds sheets, never touches the
manifest). Pure-key #FF00FF pockets are gone from every HD webp.
Legendaries (cap 1, boss-only): Butcher's Oath, Second Skin, Twin Sidearm,
Crimson Metronome, Abattoir Engine, Gore Crown, Thousand Teeth, Hollow Father,
The Last Cut, Meat Grinder. Once-per-floor flags reset in nextFloor.
Balance fixes: Ghoul Heart now +4 HP (2 full hearts); Brass Magazine ammo
efficiency uses the same diminishing additive formula as Scrap Feed.
Quintine
