t27b: the orphan-ceiling ledger does not name cli/t27b

#5979 added cli/t27b to the workspace but not to docs/reports/orphan_modules.json. On master, the 'Every source file is reachable from its crate root' check fails with 'cli/t27b: no ceiling in docs/reports/orphan_modules.json', and cli-tri fails modreach::tests::the_ratchet_watches_every_member_and_no_ghost. cli/t27b has 11 files under src/, all compiled, 0 orphaned. Fix: add a ceiling of 0.