The shipped default scale had no test: make_session only builds matcher-backend
engines, so scale == "local" in _on_classified never ran in the suite - and
that is the branch that was wrong twice (the rank re-sort, and the early return
that made the text lane's fill-in job unreachable).
Adds LocalScaleEngine, which injects the lanes' evidence into the live path, and
two live tests: a text-only read still labels the track, and a text veto blocks a
local accept. Adds DecisionPolicyTests for the veto/fill-in boundary, including
the lane-order-vs-value case that the rank re-sort broke.
Both regressions were re-injected to confirm the tests fail for the intended
reason: restoring the early return fails the fill-in test, and re-sorting the
lane output by value fails the order test. Suite 251 -> 261.