CLI arguments appear to not be properly typed

[seawatts]

https://github.com/denali-js/denali/blob/82401b4517b94426c3d723981eafad6356fd39cf/commands/server.ts#L98

[knownasilya]

Args are always strings, so we need to do an explicit check here.

[davewasmer]

This line should be converting the arg to a typed variable. Perhaps this is a larger bug.

https://github.com/denali-js/denali/blob/82401b4517b94426c3d723981eafad6356fd39cf/commands/server.ts#L51

Updating the title to reflect