bug(state): a quoted STATE.md milestone gains an escape layer in state.json on every state.* write (split from #4998) #5246

Split out of #4998 at the maintainer's request in the #5234 review: this issue covers only the issue's first half, the milestone escaping. The record-session half (orphaned tail line of a wrapped value, stopped_at replacement, the added **Stopped at:** line) stays on #4998.

Pre-submission checklist

• I have searched existing issues and this bug has not already been reported (it is the first half of bug(state): state.* writes add one layer of escaping to a quoted milestone value on every call; record-session also truncates multi-line Session Continuity prose #4998, split out so it can be tracked and closed on its own)

GSD Version

next @ 13d37238b (1.16.0); originally reported on 1.14.0 in #4998

Runtime

Claude Code

Operating System

macOS

Node.js Version

v24.19.0

Installation Method

Source checkout of next (npm run build:lib)

What happened?

A milestone: value that YAML has to double-quote (one containing a literal ") is read back from STATE.md as its on-disk YAML text, quotes and backslashes included, and that text is written into state.json as the value. Every state.* write adds one more escape layer.

Root cause: three readers in src/roadmap-parser.cts (extractCurrentMilestoneScoped, getMilestoneInfo, currentMilestoneRawRanges) match ^milestone:\s*(.+) against the raw file text instead of reading the frontmatter parser's decoded value.

What did you expect?

state.json carries the decoded milestone value ("v1.1 — Example milestone", including its literal quotes), unchanged across writes.

Steps to reproduce

1. STATE.md frontmatter contains milestone: "\"v1.1 — Example milestone\"".
2. Run gsd-tools query state.begin-phase --phase 3 --name Example --plans 2.
3. state.json now has "milestone": "\"\\\"v1.1 — Example milestone\\\"\"". That is the YAML source text, not the value.

On next I could not reproduce STATE.md's own frontmatter growing (#4998 reported that on 1.14.0). begin-phase, add-decision, record-metric, record-session and state sync, three rounds each, left it byte-identical. The state.json symptom reproduces every time.

How often does this happen?

Every time (100% reproducible)

Impact

Minor — Cosmetic or edge case

Additional context

Fix in #5234: the three readers go through rawFrontmatterField (the frontmatter parser's decoded value, FAILSAFE schema).

Privacy Checklist

• I have reviewed all pasted output for PII (usernames, paths, API keys) and redacted where necessary