bug(cli): links --type errors on builds and TestFlight commands never list valid values

Summary

Same gap as #2596 (fixed for versions links in #2608): asc builds links and the TestFlight links commands print a bare --type is required / invalid-value error without enumerating the accepted relationship types.

What to do

Reuse the pattern from #2608: enumerate the valid --type values in both the missing-required and invalid-value errors and in flag help; make 404s name the missing resource. No default.

Acceptance criteria

• cmdtest per command: omitted and invalid --type → exit 2 with the value list
• help lists the values; docs regenerated if help changed