Refactor Constants: Domain-Specific Modules Using Namespace Pattern

The current constants defined in src/shared/config/constants.ts are exported together, which can lead to unrelated exports being grouped improperly. To improve modularity and maintainability, refactor the constants by grouping related route and feature constants into domain-specific modules using the namespace pattern. This approach will enhance clarity, prevent namespace pollution, and facilitate easier management of constants across the codebase.