feat(creatures): add creature types, data, ECS components, and core systems

Phase 5.1-5.5: Creatures & Ecology foundation
- 3 species data (Crystallid, Acidophile, Reagent) with real chemistry
- ECS components: Creature, AI, Metabolism, LifeCycle
- AI FSM system: idle → wander → feed → flee → attack
- Metabolism: energy drain, feeding from resources, starvation damage
- Life cycle: egg → youth → mature → aging → natural death
- Population dynamics: counting, reproduction, initial spawning
- Species registry with numeric/string ID lookup
- 51 tests passing (272 total)

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

src/creatures/types.ts

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+/**
+ * Creature Types — data definitions for the creature/ecology system
+ *
+ * Three species in Catalytic Wastes:
+ * - Crystallids: slow, sturdy, eat minerals, excrete silicon
+ * - Acidophiles: medium speed, eat minerals, excrete acid
+ * - Reagents: fast, paired, predatory, explosive
+ */
+
+/** Species identifier (stored as numeric ID in ECS components) */
+export enum SpeciesId {
+  Crystallid = 0,
+  Acidophile = 1,
+  Reagent = 2,
+}
+
+/** AI behavior state (FSM) */
+export enum AIState {
+  Idle = 0,
+  Wander = 1,
+  Feed = 2,
+  Flee = 3,
+  Attack = 4,
+}
+
+/** Life cycle stage */
+export enum LifeStage {
+  Egg = 0,
+  Youth = 1,
+  Mature = 2,
+  Aging = 3,
+}
+
+/** Diet type — what a creature can feed on */
+export type DietType = 'mineral' | 'acid' | 'creature';
+
+/** Species definition loaded from creatures.json */
+export interface SpeciesData {
+  id: string;
+  name: string;
+  nameRu: string;
+  speciesId: SpeciesId;
+  description: string;
+  descriptionRu: string;
+
+  /** Visual */
+  color: string;       // hex color string
+  radius: number;      // base radius in pixels
+  radiusYouth: number; // smaller when young
+
+  /** Stats */
+  health: number;
+  speed: number;       // pixels per second
+  damage: number;      // damage per attack
+  armor: number;       // damage reduction (0-1)
+
+  /** Metabolism */
+  diet: DietType;
+  dietTiles: string[];         // tile names this species feeds on
+  excretionElement: number;    // atomic number of excreted element (0 = none)
+  energyMax: number;           // max energy capacity
+  energyPerFeed: number;       // energy gained per feeding
+  energyDrainPerSecond: number; // passive energy loss rate
+  hungerThreshold: number;     // below this → seek food (0-1 fraction of max)
+
+  /** Behavior */
+  aggressionRadius: number;  // distance to detect threats
+  fleeRadius: number;        // distance to start fleeing
+  wanderRadius: number;      // max wander distance from home
+  attackRange: number;       // melee attack range
+  attackCooldown: number;    // ms between attacks
+
+  /** Life cycle durations (ms) */
+  eggDuration: number;
+  youthDuration: number;
+  matureDuration: number;
+  agingDuration: number;
+
+  /** Reproduction */
+  reproductionEnergy: number;  // energy cost to reproduce
+  offspringCount: number;      // eggs per reproduction event
+
+  /** Population */
+  maxPopulation: number;        // per-species cap
+  spawnWeight: number;          // relative spawn density (0-1)
+  preferredTiles: string[];     // tiles where this species spawns
+}
+
+/** Runtime creature state (non-ECS, for string data lookup) */
+export interface CreatureInfo {
+  speciesId: SpeciesId;
+  speciesDataId: string;   // key into species registry
+}
+
+/** Creature species registry */
+export class SpeciesRegistry {
+  private byId = new Map<string, SpeciesData>();
+  private byNumericId = new Map<SpeciesId, SpeciesData>();
+
+  constructor(data: SpeciesData[]) {
+    for (const species of data) {
+      this.byId.set(species.id, species);
+      this.byNumericId.set(species.speciesId, species);
+    }
+  }
+
+  /** Get species by string ID */
+  get(id: string): SpeciesData | undefined {
+    return this.byId.get(id);
+  }
+
+  /** Get species by numeric ID (from ECS component) */
+  getByNumericId(id: SpeciesId): SpeciesData | undefined {
+    return this.byNumericId.get(id);
+  }
+
+  /** Get all species */
+  getAll(): SpeciesData[] {
+    return [...this.byId.values()];
+  }
+
+  /** Get species count */
+  get count(): number {
+    return this.byId.size;
+  }
+}