v0.18.0 — map lane: multi-session planning, and a road into greenfield

Minor: the map lane — multi-session planning above the pipeline, and a road into greenfield. Concept adapted from Matt Pocock's wayfinder skill (MIT); the enforcement layer is Espalier's.

• /espalier-map lane — big efforts charted as decision maps under espalier/maps/{date}-{slug}/: map.md index + one file per ticket (grilling|prototype|research|task, blocked_by, claimed_by) + assets/. File-per-ticket = no cross-ticket merge conflicts; claims are the lock; the frontier is grep-derivable. Chart mode names the destination first and fans out breadth-first; work mode resolves one non-research ticket per session. Cleared maps hand off as FILED change skeletons — audit chain reads decision → ticket → change → commit.
• map-guard.sh (all three platforms) — plan-don't-do, machine-verified: while a fresh .active-session marker exists, Write/Edit outside espalier/maps/ is blocked. User-approved allow: prefix write windows; stale markers self-expire. Upstream wayfinder's most-reported failure (production code written mid-map) is closed structurally.
• Grill mode=decision — sharp-question grilling for map tickets.
• Greenfield decide-then-bind — /espalier-init + bootstrap path for empty repos and boilerplates.
• espalier-stats.sh — lane-quality Layer 3 report hook.
• eval/map harness — Layer 2 lane-quality gate: 10-fixture run PASS 1.00; judge validated 42/42 (dual-LLM proxy hand-score); shadow fixtures; validate-judge.sh judge-validation harness.

Suites: bootstrap 197/197, hooks 146/146; validation 50/55/60 by platform set (new checks 59-60). Migration #25 (v0.17.0→v0.18.0) included.

Full detail: CHANGELOG.md 0.18.0.