* GH-10761: Migrate Post.Get to sync by default
* instantiate storeChannel with make
* fix go vet issue
* fix go vet issue
* use select for checking channel for value
* fix go vet shadow variable issue
* addressing review comments
* call post.Get() in goroutine
* refactor minor values to fix tests
* fix: remove err error type, it should be *model.AppErr