feat: add maps-to link type and GSD milestone consistency check to mgw:sync

[snipcodeit]

Summary

Add maps-to as a recognized cross-ref link type (milestone:N ↔ gsd-milestone:name). Add GSD milestone consistency check in mgw:sync: for each maps-to link, verify the GSD milestone exists in .planning/MILESTONES.md or as active ROADMAP.

Cross-ref Format

{ "a": "milestone:3", "b": "gsd-milestone:v1.0", "type": "maps-to", "created": "..." }

Files

• commands/link.md — add maps-to link type, milestone:N and gsd-milestone:name normalization
• commands/sync.md — add GSD milestone consistency check in check_each step

GSD Route

gsd:quick

Depends On

• A3 (milestone mapper creates the maps-to entries)

[snipcodeit]

MGW execution-complete · 2026-03-01T00:00:00Z
Milestone: v3 — Multi-Milestone Tracking | Phase 25: Cross-Milestone Operations

Implementation Complete

Implemented in commits 88ef17d (maps-to link type) and c6fc5c8 (sync check) on branch feat/mgw-gsd-architecture-repair.

• commands/link.md: added maps-to link type with milestone:N and gsd-milestone:id reference normalization
• commands/sync.md: added GSD milestone consistency check — for each maps-to cross-ref, verifies the GSD milestone ID exists in .planning/ROADMAP.md or .planning/MILESTONES.md, reports stale mappings

Part of PR #102.