feat(client): add Timestamp component, ESLint 10 + Prettier, and code quality fixes

- add Timestamp component with moment relative time and ISO tooltip
- add Timestamp stories (JustNow, MinutesAgo, HoursAgo, DaysAgo, MonthsAgo)
- add ESLint 10 with typescript-eslint, react-hooks, react-refresh, prettier
- add Prettier config with singleQuote, semi, trailingComma all, printWidth 100
- add lint, lint:fix, format, test:storybook scripts to package.json
- fix react-hooks/set-state-in-effect in all page components
- auto-fix 113 Prettier formatting issues across src and .storybook

client/.storybook/stories/Card.stories.tsx

@@ -30,16 +30,29 @@ export const Default: Story = {
 export const ScenarioCard: Story = {
   render: () => (
     <Card>
-      <div style={{ display: 'flex', justifyContent: 'space-between', alignItems: 'flex-start', marginBottom: 8 }}>
+      <div
+        style={{
+          display: 'flex',
+          justifyContent: 'space-between',
+          alignItems: 'flex-start',
+          marginBottom: 8,
+        }}
+      >
         <span style={{ fontWeight: 600, fontSize: 14 }}>Login flow</span>
-        <Badge variant="success" dot>Passed</Badge>
+        <Badge variant="success" dot>
+          Passed
+        </Badge>
       </div>
       <p style={{ margin: '0 0 16px', fontSize: 13, color: 'var(--color-text-muted)' }}>
         Last run 2 minutes ago · 4 steps
       </p>
       <div style={{ display: 'flex', gap: 8 }}>
-        <Button size="sm" variant="primary">Run</Button>
-        <Button size="sm" variant="ghost">Edit</Button>
+        <Button size="sm" variant="primary">
+          Run
+        </Button>
+        <Button size="sm" variant="ghost">
+          Edit
+        </Button>
       </div>
     </Card>
   ),