Phase 6: character creation & level-up

- Ability generation: standard array, point buy (27-pt, validated), 4d6kh3 roll;
  AbilityGenModal with assign-from-pool + steppers (pure abilityGen lib + tests)
- Level-up flow: increment level, HP gain (average or roll hit die + CON)
- Print / save-to-PDF: print button + @media print hides app chrome and roll tray
- Plan: added Phase 11 (data-driven Assistant) to the roadmap

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/lib/rules/abilityGen.test.ts

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+import { describe, it, expect } from 'vitest';
+import { rollAbilityScores, pointBuySpent, pointBuyRemaining, pointCost, STANDARD_ARRAY } from './abilityGen';
+import { createRng } from '@/lib/rng';
+
+describe('ability generation', () => {
+  it('standard array is the canonical spread', () => {
+    expect([...STANDARD_ARRAY]).toEqual([15, 14, 13, 12, 10, 8]);
+  });
+
+  it('rolls six scores each in 3..18', () => {
+    const scores = rollAbilityScores(createRng('chargen'));
+    expect(scores).toHaveLength(6);
+    for (const s of scores) {
+      expect(s).toBeGreaterThanOrEqual(3);
+      expect(s).toBeLessThanOrEqual(18);
+    }
+  });
+
+  it('point-buy costs match the standard table', () => {
+    expect(pointCost(8)).toBe(0);
+    expect(pointCost(13)).toBe(5);
+    expect(pointCost(15)).toBe(9);
+    expect(pointCost(16)).toBeNull();
+    expect(pointCost(7)).toBeNull();
+  });
+
+  it('27-point standard build is exactly spent', () => {
+    // all 13s costs 30 (>27), but 15,15,15,8,8,8 = 9+9+9 = 27
+    expect(pointBuySpent([15, 15, 15, 8, 8, 8])).toBe(27);
+    expect(pointBuyRemaining([15, 15, 15, 8, 8, 8])).toBe(0);
+    expect(pointBuyRemaining([8, 8, 8, 8, 8, 8])).toBe(27);
+    expect(pointBuySpent([16, 8, 8, 8, 8, 8])).toBe(Infinity);
+  });
+});

src/lib/rules/abilityGen.ts

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+import type { Rng } from '@/lib/rng';
+import { createRng } from '@/lib/rng';
+import { rollDice } from '@/lib/dice/notation';
+
+/** The classic 5e/PF2e-ish standard array. */
+export const STANDARD_ARRAY = [15, 14, 13, 12, 10, 8] as const;
+
+/** Roll six ability scores as 4d6, drop the lowest. */
+export function rollAbilityScores(rng: Rng = createRng()): number[] {
+  return Array.from({ length: 6 }, () => rollDice('4d6kh3', rng).total);
+}
+
+/**
+ * Point-buy (27-point standard). Scores 8–15; costs 0,1,2,3,4,5,7,9 for 8..15.
+ * Returns the cost of a single score, or null if out of the buyable range.
+ */
+const POINT_COST: Record<number, number> = { 8: 0, 9: 1, 10: 2, 11: 3, 12: 4, 13: 5, 14: 7, 15: 9 };
+export const POINT_BUY_BUDGET = 27;
+export const POINT_BUY_MIN = 8;
+export const POINT_BUY_MAX = 15;
+
+export function pointCost(score: number): number | null {
+  return score in POINT_COST ? POINT_COST[score]! : null;
+}
+
+/** Total points spent across six scores (Infinity if any score is out of range). */
+export function pointBuySpent(scores: number[]): number {
+  let total = 0;
+  for (const s of scores) {
+    const c = pointCost(s);
+    if (c === null) return Infinity;
+    total += c;
+  }
+  return total;
+}
+
+export function pointBuyRemaining(scores: number[]): number {
+  return POINT_BUY_BUDGET - pointBuySpent(scores);
+}