Add mcp server, adjust types, add logger

[dlebech]

This pull request primarily improves type safety and consistency throughout the codebase by centralizing shared types in types/app, refactoring component props and internal logic to use these types, and cleaning up type-related workarounds. Additionally, it introduces a new logging dependency and configuration for development tooling.

Type Safety and Refactoring

• Centralized shared types such as CategoryOption, CategoryExpense, DisplayTransaction, DisplayTransactionGroup, and NestEntry in types/app, and refactored imports and component props across multiple files to use these types instead of local/interface duplication. This reduces redundancy and improves type consistency. [1] [2] [3] [4] [5] [6] [7] [8]

• Updated selector and reducer logic in components like Charts.tsx, Transactions.tsx, and chart components to use the new types, and replaced any/manual casting with safer, more explicit type assertions or @ts-expect-error where necessary due to d3-collection limitations. [1] [2] [3] [4] [5] [6]

• Refactored CategorySelect to use the shared CategoryOption type, improved the findValue utility for more robust value resolution, and ensured compatibility with readonly arrays from react-select. [1] [2] [3] [4]

Logging and Error Handling

• Replaced console.error with a centralized logger.error in API route handlers for better logging consistency, and added the loglevel package as a dependency. [1] [2] [3] [4] [5]

Development Tooling

• Added a .mcp.json configuration file to support the next-devtools-mcp development tool.

Test Data Consistency

• Updated mock Redux state in Intro.test.tsx to match the latest state shape, ensuring tests remain accurate and up-to-date.