Large refactor that renames/moves core types into a new Govor.Domain surface and reorganizes the Application layer. Models, configurations, migrations and many files moved from Govor.Core/Govor.Data to Govor.Domain; numerous Application services, interfaces and implementations were relocated or added (authentication, friends, messages, medias, push notifications, user sessions, storage, synching, private chats, etc.). Tests updated to use Govor.Domain namespaces and adjusted project references (removed Govor.Data reference from API tests). Also updated API, Hub and mapping code and project files to reflect the new structure and naming. This is primarily a codebase-wide namespace and module reorganization to establish a Domain project and restructure application services.
Added refresh token endpoint and controller, introduced IUserSessionRefresher and UserSessionRefresher for token renewal, and updated session handling to return both access and refresh tokens. Refactored AuthController, tests, and related interfaces to support new token flow. Fixed JwtAccessOption property typo, updated configuration, and extended UserSessionsRepository to support lookup by refresh token.