✨ 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/docs/e2e/README.md

@@ -0,0 +1,7 @@
+# E2E Test Reports
+
+[<- Up to docs](../README.md)
+
+| Test | Status | Duration |
+|------|--------|----------|
+| [home page loads and shows server health info](./home-page-loads-and-shows-server-health-info.md) | PASSED | 168ms |

frontend/docs/e2e/home-page-loads-and-shows-server-health-info.md

@@ -0,0 +1,16 @@
+# home page loads and shows server health info
+
+[<- Back to index](./README.md) | [Top](../README.md)
+
+**File**: `tests/e2e/health.spec.ts`
+**Status**: PASSED
+**Duration**: 168ms
+
+## Screenshot
+
+![home page loads and shows server health info](../../tests/e2e/screenshots/home-page-loads-and-shows-server-health-info.png)
+
+## Test Details
+
+- Start Time: 2026-05-03T14:38:42.958Z
+- Spec File: health.spec.ts