DOCFIX-132/133: S-class cleanups -- S7 dead code + S4 trust_filter.py consolidation ...

S7: remove unused CF (d011-04) + subsumed vr_is_ipv4 guard (d011-03), no behavior change.
S4: three inline python trust filters -> one fixture-tested scripts/trust_filter.py
(--fields/--trustor-in/--first/--error-token); SDIR added to offboard + acceptance;
new tests/trust_filter/ 9/9. Gauntlet 39 ALL GREEN, offboard 22/22, acceptance 16/16.
S8 re-scoped (bigger than estimate) -- operator decision logged in ledger.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>