M0: план разработки, техническая структура, каркас проекта

- docs/PLAN.md — план по этапам, обновляется по мере работы
- docs/TECHNICAL.md — слои, карта папок, контракты, рабочие процессы
- docs/DECISIONS.md — журнал решений, принятых самостоятельно
- разрешение 1080x1920, fit-width (портрет, 4:3..21:9)
- каркас assets/scripts (core / modules / app / ui)
- headless-тесты на vitest + strict typecheck + защита чистоты core
- Rng: детерминированный генератор и перемешивание

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

assets/scripts/core/util/Rng.ts

@@ -0,0 +1,65 @@
+/**
+ * Deterministic pseudo-random generator.
+ *
+ * The whole rules core is reproducible from a seed: given the same seed and the
+ * same sequence of actions, a match replays identically. That is what lets a bug
+ * report be a single integer, and what keeps the soak tests meaningful.
+ *
+ * Algorithm is mulberry32 — small, fast, and good enough for shuffling cards.
+ * Its entire state is one 32-bit integer, so it serialises into the save/state
+ * without ceremony.
+ */
+export class Rng {
+    private _state: number;
+
+    constructor(seed: number) {
+        // Force to uint32 so a negative or fractional seed still behaves.
+        this._state = seed >>> 0;
+    }
+
+    /** Current internal state, for serialising a game in progress. */
+    get state(): number {
+        return this._state;
+    }
+
+    /** Restores a generator to a previously captured state. */
+    static fromState(state: number): Rng {
+        return new Rng(state);
+    }
+
+    /** Uniform float in [0, 1). */
+    next(): number {
+        this._state = (this._state + 0x6d2b79f5) >>> 0;
+        let t = this._state;
+        t = Math.imul(t ^ (t >>> 15), t | 1);
+        t ^= t + Math.imul(t ^ (t >>> 7), t | 61);
+        return ((t ^ (t >>> 14)) >>> 0) / 4294967296;
+    }
+
+    /** Uniform integer in [0, bound). `bound` must be positive. */
+    nextInt(bound: number): number {
+        if (bound <= 0) {
+            throw new RangeError(`Rng.nextInt bound must be positive, got ${bound}`);
+        }
+        return Math.floor(this.next() * bound);
+    }
+
+    /** Uniformly picks one element. Throws on an empty array. */
+    pick<T>(items: readonly T[]): T {
+        if (items.length === 0) {
+            throw new RangeError('Rng.pick called on an empty array');
+        }
+        return items[this.nextInt(items.length)];
+    }
+
+    /** Fisher-Yates, in place. Returns the same array for convenience. */
+    shuffle<T>(items: T[]): T[] {
+        for (let i = items.length - 1; i > 0; i--) {
+            const j = this.nextInt(i + 1);
+            const tmp = items[i];
+            items[i] = items[j];
+            items[j] = tmp;
+        }
+        return items;
+    }
+}