A document rendered after the LEGS table broke is accepted as current by
the pre-fix parser with no gate column at all, so mutant-doc-drifts alone
would pass a tree that never had the column. The new leg reads that same
mutant's fresh render and requires rc 0 with a '-' cell, pinning the
failure mode the repair removes.
Measured: q132_verify.py 9 legs, 0 fault, rc 0.
Q130's closed-artifacts leg added "path": os.path.join(...) to verify.py's
LEGS, so ast.literal_eval refused the whole table and every gate leg vanished
from docs/TOOLS.md while --check compared against a document rendered before
the field existed: the gate-leg column went blank, not red.
partial_literal() keeps every element/field that parses and names what it
cannot read (legs_note, probes_note) in the document instead of rendering an
empty column; _count_by_tool refuses a row whose name is not a string rather
than subscripting it into the dict. Selftest 20 -> 23 cells, pin moved with
it, docs/TOOLS.md re-rendered (23 tools, 10 gate legs).