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/clients/client-detail.tsx

@@ -1,7 +1,6 @@
 'use client';
 
 import { useQuery } from '@tanstack/react-query';
-import { useParams } from 'next/navigation';
 
 import { DetailLayout } from '@/components/shared/detail-layout';
 import { ClientDetailHeader } from '@/components/clients/client-detail-header';