Head vocabulary gets one owner, and the holdout says the recovery generalizes

The recovery carried its own copy of the head words. That is the drift
legalReferenceGrammar was extracted to end, one module along: the first time
a jurisdiction, era or house style adds a container word to CONTAINER_RE,
a duplicated vocabulary in the recovery silently stops following it and the
detector quietly loses exactly the documents the new word was added for.
CONTAINER_WORDS / SCHEDULE_WORDS / SECTION_WORDS / DECIMAL_LABEL are now
named once and consumed by both the per-line matchers and SENTENCE_JOIN_RE.
The terminator class is widened to closing brackets and guillemets for the
same reason - the guard is about the ANTECEDENT, not a punctuation dialect.
Behaviour-identical on the mini corpus (16 refused / 4,414 resolved / 9.1%).

GENERALIZATION, the number that matters more than the mini corpus. The
LegalBench-RAG holdout split is 55 documents (17 contractnli, 20 cuad, 18
maud) derived by skipping every document the mini derivation touched, so it
is disjoint by construction and nothing in this round was tuned on it. Run
once, question-blind, baseline 285b86f7 -> HEAD:

  documents refused   14 -> 9      (maud 9 -> 5, cuad 3 -> 2, contractnli 2)
  references resolved 3,879 -> 5,150  (+33%; maud 3,368 -> 4,520)
  accepted refs miss  17.2% -> 10.5%  (maud 17.8% -> 10.3%)
  detected 12,025 and external 2,008 UNCHANGED

Same direction, same shape, similar magnitude as the corpus the thresholds
were placed on, and the miss rate falls while 27% more references are
accepted. The mechanisms are extraction facts rather than drafting
conventions - a run of spaces is a lost line break, a heading follows the
end of a line - which is why they carry.

Census script takes XREF_SPLIT / XREF_CORPUS so the two splits and a
baseline worktree run the identical instrument.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01H9ToHYJVDxfeJcJwdzrP2H