Update internal module imports to use v5 package path

- Updated all `github.com/luispater/CLIProxyAPI/internal/...` imports to point to `github.com/luispater/CLIProxyAPI/v5/internal/...`.
- Adjusted `go.mod` to specify `module github.com/luispater/CLIProxyAPI/v5`.

internal/api/middleware/request_logging.go

@@ -8,7 +8,7 @@ import (
 	"io"
 
 	"github.com/gin-gonic/gin"
-	"github.com/luispater/CLIProxyAPI/internal/logging"
+	"github.com/luispater/CLIProxyAPI/v5/internal/logging"
 )
 
 // RequestLoggingMiddleware creates a Gin middleware that logs HTTP requests and responses.