Wire ROADMAP.md through the standards docs

ROADMAP.md was named as a destination in two places but never created,
indexed, or read back. Add the convention to how-i-work.md, note it after
the README decision tree and in the loads-when table, give it a row in the
portability layer table, make the retrofit prompt create it, and have
handoff seed it and pull from it when Current state's next steps run thin.

README.md

@@ -24,12 +24,15 @@ The governing question: **would a different agent need this to work on the repo?
 6. **Must happen deterministically, every time, no matter what the model decides?** → a hook (`.claude/settings.json`), not markdown. Markdown is guidance a model can interpret; a hook is a shell command the harness always runs. Advanced and Claude-specific — an execution-layer tool to reach for only when guidance-that-can-be-ignored isn't enough. Not needed to start.
 7. **Discovered mid-work?** → auto memory holds it for now; promote durable facts into AGENTS.md, since auto memory is never committed or backed up.
 
+*The tree above routes durable **guidance**. Project **state** is tracked separately: near-term status and next steps in AGENTS.md's `## Current state` section; longer-term backlog in `ROADMAP.md` at the repo root.*
+
 ## What loads when
 
 | Layer | Loads | After `/compact` |
 |---|---|---|
 | `how-i-work.md` (via `~/.claude/CLAUDE.md`) | In full, every session | Re-read |
 | `AGENTS.md` (via `CLAUDE.md` symlink) | In full, every session | **Re-read from disk** |
+| `ROADMAP.md` | Only when you open it deliberately | n/a — never auto-loaded |
 | `docs/guides/*` (via `.claude/rules/` symlinks) | Only when files matching `paths:` are opened | **Not re-injected** — promote anything chat-only into AGENTS.md before compacting |
 | Skills | On invocation / relevance | n/a |
 | Subagents | Isolated context window; returns a summary | n/a |