feat(game): implement Quantum Runner core game loop prototype

[Chris-Moller]

Summary

• Implemented complete Quantum Runner prototype: a turn-based grid game where the player selects which stochastic future to collapse into rather than directly controlling movement
• Built with TypeScript + Vite + HTML5 Canvas 2D, targeting a "terminal phosphor" visual aesthetic
• Includes a 12x10 grid level with corridors, 2 enemy pursuers, and a verified-navigable path from start to exit

Architecture

• State layer (src/state/): Immutable game state model, grid with BFS-verified pathfinding, entity factories
• Engine (src/engine/): Stochastic futures generation with weighted random movement, enemy chase AI, quality variance via oversampling + spread selection
• Renderer (src/render/): Canvas 2D rendering with grid, entities, future overlay (ghost entities, dashed arrows, quality-colored highlights), scanline effect
• UI (src/ui/): State machine game controller (title → playing → win/lose), turn manager for streaming futures, HUD, keyboard + click input

Acceptance Criteria Met

• Grid-based level with protagonist, goal, and enemies
• N futures per turn (configurable 2-5, default 3)
• Streaming Accept/Pass decision interface
• Passed futures cannot be revisited; last is auto-applied
• Visual future overlay with ghost entities and arrows
• Win (reach exit) and lose (caught by enemy) conditions
• Meaningful quality variance in futures
• Restart after win/loss
• Responsive core game loop

Test plan

• TypeScript strict mode compiles without errors
• Vite production build succeeds
• BFS verification confirms grid is navigable from player start to goal
• Manual playtesting in browser to verify gameplay feel

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