Phase 0 fun-yield prototype for the browser-native page-as-level game.
The current build has the v1 level-script schema locked, validates three placeholder levels at module load, renders a PixiJS three-tile preview for the longform, reference, and commerce archetypes, and starts a first interactive SURGE run when a tile is clicked. This checkpoint supports calm and obstacle-wave acts, collision scoring, results, and local best scores; backend, accounts, compiler, extension, audio, HUD polish, sharing, and additional act behaviors remain intentionally out of scope for Phase 0.