Title screen rewrite, walking-scene parallax, global DEBUG menu

TitleScreen is rewritten — poster background, SVG gold-gradient title with ink stroke, PLAY button restyled to match BottomMenu (grey + speedLines + selected sheen), and six color-tinted SparkleField squares positioned at character hand locations. The dev-only Skip Tutorial / Full Access / Skip up to Library buttons that used to crowd the title screen are gone from there.

The walking-battle scene gains a `biome` field that resolves to four stacked PNG layers (sky/back/mid/fore) rendered behind the scene; back and mid tile as parallax while sky and fore stay viewport-locked. Enemy triggers now render as creature sprites via getEnemyTriggerImage, with the colored placeholder gone so the new artwork shows through cleanly. Trigger zones are sized from BATTLE_ENEMY_TRIGGER_* (1000-ref units, scaled), so enemies match the story/front.png aspect and align with the hero walking row.

All the dev-only entry points — three walkthrough seeders, Fight Lab, Log Out, Delete Player, and the trigger debug overlay toggle — now live behind a single compact red DEBUG button top-left on every screen. The Settings → Profile debug surface and the title-screen debug buttons are gone; the e2e helper drives the new DEBUG → Skip Tutorial path.