Add core models, DTOs, and services for EchoHub chat application

- Created User, Channel, Message, and ServerInfo models with necessary properties.
- Added DTOs for user profiles, server information, and message handling.
- Implemented JWT authentication service for user login and token generation.
- Developed Entity Framework Core DbContext for database interactions.
- Introduced SignalR ChatHub for real-time messaging and presence tracking.
- Implemented file storage and image to ASCII conversion services.
- Set up CORS and middleware for API endpoints.
- Created launch settings and development configuration for server and web projects.

.gitignore

@@ -410,9 +410,18 @@ FodyWeavers.xsd
 # Built Visual Studio Code Extensions
 *.vsix
 
+# Dev folder
+.dev/
+
 # Windows Installer files from build outputs
 *.cab
 *.msi
 *.msix
 *.msm
 *.msp
+
+.dev/*
+appsettings.json
+CLAUDE.md
+*.db
+*.db-*