✨ feat(frontend): Storybook + auto-generated Playwright e2e docs with screenshots (#30)

Storybook 8 + Playwright JSON reporter + auto-generated markdown docs with embedded screenshots and breadcrumbs. Frontend PRs now reviewable from Gitea web UI. ~95% Mistral autonomous via ICM workspace, trainer commit/PR (Mistral hit turn limit).

Co-authored-by: Gabriel Radureau <arcodange@gmail.com>
Co-committed-by: Gabriel Radureau <arcodange@gmail.com>

frontend/playwright.config.ts

@@ -1,10 +1,19 @@
 import { defineConfig } from '@playwright/test'
+import path from 'path'
+
 export default defineConfig({
   testDir: './tests/e2e',
   timeout: 30_000,
+  reporter: [
+    ['list'],
+    ['json', { outputFile: path.join(process.cwd(), 'test-results', 'results.json') }],
+  ],
   use: {
     baseURL: 'http://localhost:3000',
+    screenshot: 'on',
+    video: 'off',
   },
+  outputDir: 'test-results/output',
   webServer: {
     command: 'npm run dev',
     url: 'http://localhost:3000',