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/lib/db/schema/relations.ts

@@ -67,7 +67,6 @@ import {
   savedViews,
   scratchpadNotes,
   userNotificationPreferences,
-  currencyRates,
   customFieldDefinitions,
   customFieldValues,
 } from './system';