- Reduce playfield from 20x15 to 10x15 tiles (60x60px) and center in canvas
- Replace raw pixel math with tile-based coordinate helpers (`_px`, `_py`, `_col`, `_row`)
- Rewrite player movement to use hard-snap alignment and tile-center turning thresholds
- Switch ghosts to tile-target-based navigation with `_pickNextTarget` and distance checks
- Update layout to a symmetric 10-column maze with ghost house and corridors
- Redraw HUD and background for the new layout dimensions