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

Adds three things to make frontend PRs reviewable directly from Gitea web UI:

1. Storybook 8 for Vue 3 components
   - .storybook/main.ts + preview.ts
   - HealthDashboard.stories.ts (1 example story)
   - npm run storybook / npm run build-storybook

2. Playwright JSON reporter + screenshot on every test
   - playwright.config.ts: json reporter + screenshot: 'on'
   - health.spec.ts: explicit screenshot path

3. Auto-generated markdown docs with breadcrumbs
   - scripts/generate-test-docs.mjs: reads results.json -> generates docs/e2e/<test>.md per test
   - docs/README.md: top-level frontend docs index
   - docs/e2e/README.md: e2e index with link to each test
   - Each test markdown has breadcrumb [<- Back to index]
   - Screenshots embedded via relative path

Companion to PR #25 (Nuxt scaffold).

Out of scope (future PRs):
- Visual regression testing
- Storybook deployment / hosted preview
- More e2e test coverage

🤖 Co-Authored-By: Mistral Vibe <vibe@mistral.ai>

frontend/scripts/generate-test-docs.mjs

@@ -0,0 +1,120 @@
+#!/usr/bin/env node
+
+import fs from 'node:fs/promises'
+import path from 'node:path'
+import { fileURLToPath } from 'node:url'
+
+const __dirname = path.dirname(fileURLToPath(import.meta.url))
+const frontendDir = path.resolve(__dirname, '..')
+
+const resultsPath = path.join(frontendDir, 'test-results', 'results.json')
+const docsDir = path.join(frontendDir, 'docs', 'e2e')
+const screenshotsDir = path.join(frontendDir, 'tests', 'e2e', 'screenshots')
+
+async function main() {
+  // Read results
+  const resultsText = await fs.readFile(resultsPath, 'utf8')
+  const results = JSON.parse(resultsText)
+
+  // Create output directories
+  await fs.mkdir(docsDir, { recursive: true })
+
+  // Extract tests from suites
+  const testDocs = []
+  for (const suite of results.suites || []) {
+    for (const spec of suite.specs || []) {
+      for (const test of spec.tests || []) {
+        for (const result of test.results || []) {
+          const testInfo = {
+            title: spec.title,
+            specFile: spec.file || suite.file,
+            status: result.status,
+            duration: result.duration,
+            startTime: result.startTime,
+            attachments: result.attachments || [],
+          }
+          testDocs.push(testInfo)
+        }
+      }
+    }
+  }
+
+  // Generate individual test markdown files
+  for (const test of testDocs) {
+    const slug = slugify(test.title)
+    const mdPath = path.join(docsDir, `${slug}.md`)
+    
+    // Use slug-based screenshot name (matches explicit screenshot in test)
+    let screenshotPath = `${slug}.png`
+
+    // Also try to find screenshot attachment and use its basename
+    if (test.attachments && test.attachments.length > 0) {
+      for (const attachment of test.attachments) {
+        if (attachment.contentType === 'image/png') {
+          const basename = path.basename(attachment.path)
+          // Prefer explicit screenshot name if it matches our pattern
+          if (basename !== 'test-finished-1.png' && basename !== 'test-finished-2.png') {
+            screenshotPath = basename
+            break
+          }
+        }
+      }
+    }
+
+    const absoluteScreenshotPath = path.join(screenshotsDir, screenshotPath)
+    const relativeScreenshotPath = path.relative(docsDir, absoluteScreenshotPath)
+
+    const mdContent = `# ${test.title}
+
+[<- Back to index](./README.md) | [Top](../README.md)
+
+**File**: \`tests/e2e/${test.specFile}\`
+**Status**: ${test.status.toUpperCase()}
+**Duration**: ${test.duration}ms
+
+## Screenshot
+
+![${test.title}](${relativeScreenshotPath})
+
+## Test Details
+
+- Start Time: ${test.startTime || 'N/A'}
+- Spec File: ${test.specFile}
+`
+
+    await fs.writeFile(mdPath, mdContent)
+    console.log(`Generated: ${path.relative(frontendDir, mdPath)}`)
+  }
+
+  // Generate index README
+  const indexContent = `# E2E Test Reports
+
+[<- Up to docs](../README.md)
+
+| Test | Status | Duration |
+|------|--------|----------|
+${testDocs.map(t => `| [${escapeMd(t.title)}](./${slugify(t.title)}.md) | ${t.status.toUpperCase()} | ${t.duration}ms |`).join('\n')}
+`
+
+  await fs.writeFile(path.join(docsDir, 'README.md'), indexContent)
+  console.log(`Generated: ${path.relative(frontendDir, path.join(docsDir, 'README.md'))}`)
+
+  console.log(`\nGenerated ${testDocs.length} test docs`)
+}
+
+function slugify(str) {
+  return str
+    .toLowerCase()
+    .replace(/[^\w\s-]/g, '')
+    .replace(/[\s_]+/g, '-')
+    .replace(/^-+|-+$/g, '')
+}
+
+function escapeMd(str) {
+  return str.replace(/[|\\\[\]\{\}]/g, '\\$&')
+}
+
+main().catch(err => {
+  console.error('Error:', err)
+  process.exit(1)
+})