fix: reconcile the issues stream and remove the legacy output shims

Use one canPrompt and pullNumberArguments for the comment commands, set
display preferences instead of the retired environment variables in
tests, and delete writeList, writeItem, batch, table, writeRecord(s),
the legacy column map, confirm, require, validateMilestoneFlags and
listWindow now that every command uses their replacements.

Signed-off-by: bircni <bircni@icloud.com>

internal/services/helpers.go

@@ -64,13 +64,6 @@ type Page[T any] struct {
 	Counted bool
 }
 
-// listWindow returns items [(page-1)*limit, page*limit) even when the server caps its page size
-// below limit (MAX_RESPONSE_ITEMS), and reports whether the collection continues past them.
-func listWindow[T any](limit, page int, fetch func(limit, page int) ([]T, http.Header, error)) ([]T, bool, error) {
-	window, err := listPage(limit, page, fetch)
-	return window.Items, window.More, err
-}
-
 // listPage is listWindow that also reports the collection size the server counted.
 func listPage[T any](limit, page int, fetch func(limit, page int) ([]T, http.Header, error)) (Page[T], error) {
 	items, headers, err := fetch(limit, page)