Phase 4: interactive dice & sheet rolling

- Dice notation: exploding (Nd6!) and reroll-below (Nd6r2), capped + tested
- Degrees of success / roll-vs-DC (PF2e ±10 + nat 20/1 steps; 5e crit on nat 20/1)
- Global roll tray (shared store + RollTray in layout) with animated result + degree
- Roll from the character sheet: skills, saves, and attack to-hit/damage are
  clickable and post to the tray + history (rollAndShow/rollCheck helpers)
- Saved roll macros per campaign (persisted) on the Dice page

10 new unit tests (notation explode/reroll, degrees), interactive-dice e2e.

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

e2e/interactive-dice.spec.ts

@@ -0,0 +1,38 @@
+import { test, expect } from '@playwright/test';
+
+test.beforeEach(async ({ page }) => {
+  await page.goto('/');
+  await page.evaluate(async () => {
+    indexedDB.deleteDatabase('ttrpg-manager');
+    localStorage.clear();
+  });
+  await page.reload();
+});
+
+test('rolling a skill from the sheet shows the roll tray', async ({ page }) => {
+  await page.getByRole('button', { name: '+ New campaign' }).first().click();
+  await page.locator('input[data-autofocus]').fill('Dice Camp');
+  await page.getByRole('button', { name: 'Create' }).click();
+  await page.getByRole('link', { name: 'Characters' }).click();
+  await page.getByRole('button', { name: '+ New character' }).first().click();
+  await page.locator('input[data-autofocus]').fill('Roller');
+  await page.getByRole('button', { name: 'Create' }).click();
+  await page.getByRole('link', { name: /Roller/ }).click();
+
+  // Click the Acrobatics modifier to roll it
+  await page.getByTitle('Roll Acrobatics (DEX)').click();
+  // The shared roll tray appears (unique dismiss control) showing the roll
+  await expect(page.getByRole('button', { name: 'Dismiss roll' })).toBeVisible();
+  await expect(page.locator('text=/= \\d+/').first()).toBeVisible();
+});
+
+test('dice page: save and use a macro', async ({ page }) => {
+  await page.getByRole('link', { name: 'Dice' }).click();
+  await page.getByLabel('Dice expression').fill('2d6+3');
+  await page.getByRole('button', { name: /Save/ }).click();
+  // Macro chip appears and rolls when clicked
+  const chip = page.getByRole('button', { name: '2d6+3', exact: true });
+  await expect(chip).toBeVisible();
+  await chip.click();
+  await expect(page.locator('text=/= \\d+/').first()).toBeVisible();
+});