refactor(converter): shared page layout + reusable conversion logic/UI

Pages:
- add WalletLayout route (WalletHeader + main + Footer via <Outlet/>),
  wrap converter/swap/bridge/transactions; thin pages, drop duplicated shell CSS
- extract SwapBridgeTabs shared between swap/bridge pages

Converter reuse (FSD layers, no widget->widget imports):
- move commission tiers to entities/commission (+ CommissionTable ui)
- shared calc hook features/payment/model/useCurrencyConversion;
  useConverterSection becomes thin wrapper; HomePage Converter reuses it
- move ConvertField/DirectionSwapButton to shared/ui; delete dead useConverter

Tooling:
- add eslint.config.js (ESLint 9 flat config); fix no-explicit-any in WalletPage

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/pages/converter/ui/ConverterPage.tsx

@@ -1,16 +1,5 @@
 import { ConverterSection } from '@widgets/converter-page'
-import { Footer } from '@widgets/footer'
-import { WalletHeader } from '@widgets/wallet-header'
-import styles from './ConverterPage.module.css'
 
 export function ConverterPage() {
-  return (
-    <div className={styles.page}>
-      <WalletHeader />
-      <main className={styles.main}>
-        <ConverterSection />
-      </main>
-      <Footer />
-    </div>
-  )
+  return <ConverterSection />
 }