Address argus review on #1938's reopen verb: public fns returning Result
need a # Errors doc per the workspace convention. Document the patch_json
and print_json failure modes.
hive-forge had close but no reopen, so reopening required the non-obvious
workaround 'issue edit <n> --state open'. Add a reopen verb mirroring close
(PATCH state=open), wired into both 'pr reopen' (kind-checked PR) and
'issue reopen' (kind-checked issue). Updates docs/forge.md + the subcommand
enumerations.