Improve Code Quality (#93, #244, #261, #268, #273)

[celticr]

Combined Implementation Task

This issue combines all code quality improvements into one cleanup task.

Tasks

1. Remove type issues (was Remove type issues on client codebase. #268)

   • Fix all TypeScript errors in client codebase
   • Resolve ESLint warnings

2. Set up ESLint (was Properly set up eslint #273)

   • Fix package version conflicts
   • Enable as pre-build script

3. Dependencies cleanup (was Sort out dependencies and devDependencies #93)

   • Sort dependencies vs devDependencies correctly
   • Remove duplicates

4. Centralize utils (was Centralize all utils in one directory instead of util.ts #244)

   • Move all utility functions to single directory

5. Update dependencies (was Update dependencies #261)

   • Run npm audit fix
   • Update outdated packages

Acceptance Criteria

• No TypeScript errors
• ESLint runs without errors
• Dependencies properly categorized
• Utils centralized
• npm audit clean (or documented exceptions)

Closes #93, #244, #261, #268, #273