chore(m170): close — sandbox proven by execution, rubric graded from green lanes

M170_001 moves to `done/`. Every Dimension is DONE except 3.5, which is
WITHDRAWN on the record rather than quietly dropped: "no executable is
reachable inside a lease" cannot hold while the engine's transport spawns a
subprocess, and asserting it would ship a runner on which no lease reaches a
model.

Six rubric rows regraded from actual lane output rather than from intent:
R5/R7 from `make test-integration-kernel` (exit 0, 438 pass / 6 skip), R8 from
its own grep, S1 from `make test-unit-all` (exit 0 — the disk exhaustion that
blocked it is gone), S5 from `make memleak` (exit 0), and S3 from CI, where
`test-integration` and `test-integration-suite` both pass. The local
integration lane reported 985 pass / 0 fail once and lost one test to a
wall-clock flake on two other runs; that test asserts `elapsed < 5_500`,
passes 3/3 in isolation on an idle machine, and lives outside this diff.

M136_001 stays IN_PROGRESS in `active/`: its §1–§5 external proof needs the
deploy and a live run, and marking it done would be the unearned claim this
milestone spent itself correcting.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>