fix: resolve telegram auth token expiration and clean up codebase

- Fix stale initData comparison in clearStaleSessionIfNeeded that destroyed
  valid refresh tokens on mobile WebView reopens
- Restrict X-Telegram-Init-Data header to auth endpoints only
- Close Mini App on auth retry to force fresh initData from Telegram
- Merge Connection page error/not-configured states for better UX
- Remove unnecessary comments across 40+ files (section dividers,
  restating comments, noise catch block comments)
- Configure ESLint allowEmptyCatch to properly handle intentional
  empty catch blocks (62 warnings resolved)

src/api/branding.ts

@@ -88,9 +88,7 @@ export const getCachedBranding = (): BrandingInfo | null => {
 export const setCachedBranding = (branding: BrandingInfo) => {
   try {
     sessionStorage.setItem(BRANDING_CACHE_KEY, JSON.stringify(branding));
-  } catch {
-    // sessionStorage not available
-  }
+  } catch {}
 };
 
 // Preload logo image as blob to hide backend URL