Changes to consume tcli as a library

[ppadmavilasom]

• Allows extensions as shown under examples/_pubsub to implement your own commands.

[sssarfrazzz]

Not able to understand the example of sns-sqs.

Please update example of petstore as well

[ppadmavilasom]

Fair point.
I have updated the example from a new project perspective. A full working example will require the current changes to go in first as the dependencies will not properly resolve without these changes in main. I will provide steps to test locally here (this will not apply as is when this branch is merged so not making it part of README)
If you want to check out how this works locally, you will have to redirect the ref locally. Assuming you create a new go project and create main.go as shown in example.
Do the following to get that project in a testable state for pubsub extensions

go mod init tcli/pubsubtest

edit go.mod to add the following (assumes you create example in the same parent folder as this project. otherwise, change redirect as applies)

go 1.26.5

require github.com/hpinc/tcli v0.0.0
replace github.com/hpinc/tcli => ../tcli

run go mod tidy and you should be able to run go run main.go now with proper config override.

petstore does not need changes. It's usage example will continue to work without changes.
Note that the usage as a lib is primarily aimed at extending tcli functionality via the x-extension mechanism to support custom commands.

[RehanChanegaon]

Reviewed the changed files. Looks good to me. +1