* Implement basic HelpScout integration

* Set 127.0.0.1 as a default customer IP in `Plans.with_prices/2`

* Use `is_nil/1` instead of `... == nil` (h/t @aerosol)

* Use `Path.join/1,2` to build API URLs a bit more safely (h/t @aerosol)

* Check for locked sites entirely within query logic

* Move conditional start of HelpScout vault to compile-time

* Include customer_id in error sent to Sentry

* Use `Plug.Crypto.secure_compare/2` for constant-time signature comparison

* Refactor token request function

* Use `Path.join/1` in one more spot

* Use route helper to build CRM URL