* api-spec: move the api-spec to root and init go.mod
* go mod tidy
* move buf files in the root as well
* gh action for api-spec changes only
* gh action for api-spec on push and pr
* introduce go.work and remove all replaces
* solve dependencies and force btcd/btcec@v2.3.3
* go work sync
* force btcd/btcec@v2.3.3
* go mod tidy