feat: add milestone-mapper logic for GSD-to-GitHub milestone creation

[snipcodeit]

Summary

After alignment analysis, map GSD milestones to GitHub milestones. Create missing GitHub milestones, backfill project.json, update cross-refs with maps-to link type.

Logic

1. Read .mgw/alignment-report.json
2. For each milestone: check if GitHub milestone with matching name exists
3. If not: create GitHub milestone + issues from phase structure
4. Write project.json with new milestone entries
5. Add cross-ref: { "a": "milestone:N", "b": "gsd-milestone:id", "type": "maps-to" }

Files

• commands/project.md — add milestone_mapper step
• commands/link.md — add maps-to link type, milestone:N and gsd-milestone:name normalization

GSD Route

gsd:quick

Depends On

• A2 (alignment-report.json must exist)
• A4 (new schema fields available)

[snipcodeit]

MGW execution-complete · 2026-03-01T00:00:00Z
Milestone: v3 — State Detection + Alignment | Phase 20: Milestone Mapper

Implementation Complete

Implemented in commit 88ef17d on branch feat/mgw-gsd-architecture-repair.

Added milestone_mapper step to commands/project.md: reads alignment-report.json, creates GitHub milestones for unmapped GSD milestones, writes maps-to cross-refs linking milestone:N → gsd-milestone:id. Also added maps-to link type normalization to commands/link.md.

Part of PR #102.