Scope debug

Print out the scope for the given schema coordinate. Maybe something like:

- `graphile schema scope Type` - types are uniquely named, so this should work across scalar, enum, object, interface, union, input object
- `graphile schema scope Type.field` - object, interface, input object
- `graphile schema scope Type.field(arg:)` - object, interface

Start by locating the `graphile schema` CLI entry point and run the coordinate examples from the issue. Done means `graphile schema scope` reports the scope for named types, fields, and field arguments across the listed schema coordinate kinds; no file or test is named in the issue.

Written by the indexing model from the issue text.