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/src/main.tsx

@@ -1,9 +1,9 @@
-import { StrictMode } from 'react'
-import { createRoot } from 'react-dom/client'
-import { HashRouter } from 'react-router-dom'
-import './i18n'
-import './ui/tokens.css'
-import App from './App'
+import { StrictMode } from 'react';
+import { createRoot } from 'react-dom/client';
+import { HashRouter } from 'react-router-dom';
+import './i18n';
+import './ui/tokens.css';
+import App from './App';
 
 createRoot(document.getElementById('root')!).render(
   <StrictMode>
@@ -11,4 +11,4 @@ createRoot(document.getElementById('root')!).render(
       <App />
     </HashRouter>
   </StrictMode>,
-)
+);