♻️ 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/HealthDashboard.stories.ts

@@ -5,6 +5,16 @@ const meta: Meta<typeof HealthDashboard> = {
   title: 'Components/HealthDashboard',
   component: HealthDashboard,
   tags: ['autodocs'],
+  parameters: {
+    docs: {
+      description: {
+        component:
+          'Smart wrapper that calls /api/healthz internally and delegates rendering to HealthDashboardView. ' +
+          'For state-by-state previews (Healthy, Loading, Error), see ' +
+          '[HealthDashboardView stories](?path=/docs/components-healthdashboardview--docs).',
+      },
+    },
+  },
 }
 export default meta
 
@@ -14,20 +24,3 @@ type Story = StoryObj<typeof meta>
 export const Default: Story = {
   args: {},
 }
-
-// Documents the loading/error visuals so reviewers see them in Storybook
-// without needing a backend down. The component currently doesn't accept overrides
-// because it uses useFetch internally - this story is a placeholder for a future
-// refactor that exposes data/pending/error as props for testability.
-export const DocumentationStub: Story = {
-  args: {},
-  parameters: {
-    docs: {
-      description: {
-        story:
-          'Renders the same as Default. The HealthDashboard fetches /api/healthz internally, so loading/error states only appear when the backend is down or slow. ' +
-          'Future improvement: accept healthData/pending/error as props for easy state-based stories. Until then, see frontend/docs/e2e/ for screenshots of both healthy and error states.',
-      },
-    },
-  },
-}