Fix all ESLint errors: remove unused imports, replace any types

- Remove ~60 unused imports and variables across 88 files
- Replace ~80 `any` type annotations with proper types (unknown,
  Record<string, unknown>, or specific types)
- Prefix unused callback args with underscore
- Fix unescaped JSX entities
- Lint now passes cleanly (0 errors, 2 intentional img warnings)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/components/portal/portal-header.tsx

@@ -16,7 +16,7 @@ export function PortalHeader({ portName, portLogoUrl, clientName }: PortalHeader
 
   async function handleLogout() {
     await fetch('/api/portal/auth/logout', { method: 'POST' });
-    router.push('/portal/login' as any);
+    router.push('/portal/login');
   }
 
   return (