Fix ESLint errors and warnings

[Mosas2000]

Closes #207

Changes

• Fixed all 21 ESLint errors (React Hook violations, parsing errors, type errors)
• Reduced warnings from 124 to 114 by removing unused imports and variables
• Replaced any types with proper TypeScript types
• Fixed setState in effect issues
• Fixed impure function calls in render
• Added proper type definitions for test mocks

Summary

• Before: 145 problems (21 errors, 124 warnings)
• After: 114 problems (0 errors, 114 warnings)
  All changes follow best practices and maintain code functionality.