feat(search): gh-style issue and pull request search tables

search issue and search pr printed rows without a header, showed merged
pull requests as closed and never said that more results exist. They now
show REPO#ID TITLE STATE AUTHOR UPDATED under a context line that counts
the matches and points at the next page, are also search issues and
search prs, take -s -L -A -l -m and @me, and use --until for --before,
which still works. Search results gain an author JSON field.

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

internal/app/args.go

@@ -62,15 +62,6 @@ func trimNames(lists ...[]string) {
 	}
 }
 
-// labelFilter splits a comma-separated label filter, trimming entries and rejecting blanks.
-func labelFilter(raw string) ([]string, error) {
-	if raw == "" {
-		return nil, nil
-	}
-	names := strings.Split(raw, ",")
-	return names, requireNames("label", "", names)
-}
-
 // oneOf rejects an enum flag value outside allowed, which needs at least two entries.
 func oneOf(flag, value string, allowed ...string) error {
 	if slices.Contains(allowed, value) {