feat: Add Storybook configuration and motion tokens implementation

- Introduced Storybook configuration files (`main.ts`, `preview.ts`, `tsconfig.json`) for Angular components.
- Created motion tokens in `motion-tokens.ts` to define durations, easing functions, and transforms.
- Developed a Storybook story for motion tokens showcasing their usage and reduced motion fallback.
- Added SCSS variables for motion durations, easing, and transforms in `_motion.scss`.
- Implemented accessibility smoke tests using Playwright and Axe for automated accessibility checks.
- Created portable and sealed bundle structures with corresponding JSON files for evidence locker.
- Added shell script for verifying notify kit determinism.

src/Web/StellaOps.Web/tests/e2e/a11y-smoke.spec.ts

@@ -0,0 +1,44 @@
+import { test, expect, Page } from '@playwright/test';
+import AxeBuilder from '@axe-core/playwright';
+import fs from 'node:fs';
+import path from 'node:path';
+
+const shouldFail = process.env.FAIL_ON_A11Y === '1';
+const reportDir = path.join(process.cwd(), 'test-results');
+
+async function writeReport(filename: string, data: unknown) {
+  fs.mkdirSync(reportDir, { recursive: true });
+  fs.writeFileSync(path.join(reportDir, filename), JSON.stringify(data, null, 2));
+}
+
+async function runA11y(url: string, page: Page) {
+  await page.goto(url);
+  const results = await new AxeBuilder({ page }).withTags(['wcag2a', 'wcag2aa']).analyze();
+  const violations = [...results.violations].sort((a, b) => a.id.localeCompare(b.id));
+  await writeReport(
+    `a11y-${url.replace(/\\W+/g, '_') || 'home'}.json`,
+    { url: page.url(), violations }
+  );
+  if (shouldFail) {
+    expect(violations).toEqual([]);
+  }
+  return violations;
+}
+
+test.describe('a11y-smoke', () => {
+  test('home page baseline', async ({ page }, testInfo) => {
+    const violations = await runA11y('/', page);
+    testInfo.annotations.push({
+      type: 'a11y',
+      description: `${violations.length} violations (set FAIL_ON_A11Y=1 to fail on any)`,
+    });
+  });
+
+  test('graph explorer shell', async ({ page }, testInfo) => {
+    const violations = await runA11y('/graph', page);
+    testInfo.annotations.push({
+      type: 'a11y',
+      description: `${violations.length} violations (/graph)`,
+    });
+  });
+});