Backend: add roomSession and roomSessionUser and more

database/migrations/.snapshot-collab_space.json

database/migrations/Migration20250319120010.ts

database/migrations/Migration20250319121248.ts

src/activities/activities.entity.ts

src/activities/activties.module.ts

src/app.module.ts

src/channel/browser.gateway.ts

src/channel/channel.gateway.spec.ts

src/channel/channel.gateway.ts

src/channel/channel.module.ts

src/channel/channel.service.ts

src/channel/channel.ts

src/channel/mock/channel.service.mock.ts

src/channel/notes.gateway.ts

src/channel/whiteboard.gateway.ts

src/points/sessionPoints.entity.ts

src/points/sessionPoints.module.ts

src/room/room.module.ts

src/room/roomSession.controller.ts

src/room/roomSession.dto.ts