♻️ refactor(frontend): split HealthDashboard into smart wrapper + dumb View for state-based stories (#33)

SRP split: HealthDashboardView (presentational, props-based) + HealthDashboard (smart wrapper, useFetch). Enables 4 Storybook stories per state + unit testability per branch. Existing testids preserved, Playwright tests still pass.

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

frontend/components/HealthDashboardView.stories.ts

@@ -0,0 +1,79 @@
+import type { Meta, StoryObj } from '@storybook/vue3'
+import HealthDashboardView from './HealthDashboardView.vue'
+
+interface ViewArgs {
+  data: {
+    status: string
+    version: string
+    uptime_seconds: number
+    timestamp: string
+  } | null
+  pending: boolean
+  error: { message: string } | null
+}
+
+const meta = {
+  title: 'Components/HealthDashboardView',
+  component: HealthDashboardView,
+  tags: ['autodocs'],
+  argTypes: {
+    pending: { control: 'boolean' },
+  },
+  parameters: {
+    docs: {
+      description: {
+        component:
+          'Pure presentational component for the health dashboard. ' +
+          'Accepts `data`, `pending`, `error` as props so all 3 states can be ' +
+          'previewed in Storybook and asserted in unit tests. The data fetching ' +
+          'wrapper is `HealthDashboard.vue`.',
+      },
+    },
+  },
+} satisfies Meta<ViewArgs>
+
+export default meta
+
+type Story = StoryObj<typeof meta>
+
+export const Healthy: Story = {
+  args: {
+    data: {
+      status: 'healthy',
+      version: '1.4.0',
+      uptime_seconds: 3600,
+      timestamp: '2026-05-03T17:30:00.000Z',
+    },
+    pending: false,
+    error: null,
+  },
+}
+
+export const Loading: Story = {
+  args: {
+    data: null,
+    pending: true,
+    error: null,
+  },
+}
+
+export const ErrorState: Story = {
+  args: {
+    data: null,
+    pending: false,
+    error: { message: '[GET] "/api/healthz": 502 Bad Gateway (simulated)' },
+  },
+}
+
+export const HealthyHighUptime: Story = {
+  args: {
+    data: {
+      status: 'healthy',
+      version: '1.5.0-rc1',
+      uptime_seconds: 86400 * 7,
+      timestamp: new Date().toISOString(),
+    },
+    pending: false,
+    error: null,
+  },
+}