Update module path for slashdevops transfer

[christiangda]

Updates repository references after the transfer from p2p-b2b to slashdevops.

Summary:

• Change the Go module path to github.com/slashdevops/textn8r.
• Update README badges, installation docs, and import examples.
• Update example module dependency/replace paths and external test imports.
• Fix the example app fmt.Println vet warning so the nested example module passes go test.

Validation:

• go test ./...
• cd examples && go test ./...