The single non-empty/non-placeholder gate caught a lone banned token
(wip) and below-floor strings, but multi-token soup made entirely of
placeholders (wip wip, tbd / na, todo todo todo) slipped through both
checks. Add an all-tokens-filler test that strips edge punctuation per
token and rejects when every meaningful token is banned — without
flagging real prose that merely contains a filler word (none of the
tests failed). Strengthens every content model + gateway anti-soup
guard that composes reject_trivial.
