Phase 0: Project setup for agent-driven development

- Phaser 3 + bitECS 0.4 + TypeScript + Vite stack
- BootScene with title screen
- 6 cursor rules (project context, agent workflow, ECS, chemistry, Phaser, data)
- Vitest configured with happy-dom
- GDD, engine analysis, implementation plan, progress tracking

Co-authored-by: Cursor <cursoragent@cursor.com>

.cursor/rules/chemistry-engine.mdc

@@ -0,0 +1,40 @@
+---
+description: Chemistry engine — real science constraints and data patterns
+globs: src/chemistry/**/*.ts
+alwaysApply: false
+---
+
+# Chemistry Engine Rules
+
+## Scientific Accuracy
+All chemical data must be **real** (simplified, never fabricated):
+- Element properties: atomic number, mass, electronegativity, group, period
+- Reactions: real products, real conditions (temperature, catalyst)
+- Failed reactions return a **reason**: "Requires catalyst", "Insufficient energy"
+
+## Element Interface
+```typescript
+interface Element {
+  symbol: string;           // "Na"
+  name: string;             // "Sodium"
+  atomicNumber: number;     // 11
+  atomicMass: number;       // 22.99
+  electronegativity: number;
+  category: ElementCategory;
+  state: MatterState;       // at room temperature
+  color: string;            // hex for rendering
+}
+```
+
+## Reaction Lookup
+Reactions indexed by **sorted reactant key** for O(1) lookup:
+```typescript
+// "Cl+Na" → { products: [{ symbol: "NaCl", ... }], ... }
+function reactionKey(symbols: string[]): string {
+  return [...symbols].sort().join('+');
+}
+```
+
+## Every Reaction Includes
+- `description`: human-readable explanation of the science
+- `failureReason`: if conditions not met, explain WHY (this is the teaching mechanism)