ROADMAP transcription: author roadmap_authority as the .dag source + fold 6 status corrections

[briansrls]

ROADMAP transcription — author roadmap_authority as the .dag source + fold the 6 status corrections

The transcription increment of the ROADMAP inversion lane (docs/plans/invert-hand-maintained.md).
Authors the real ROADMAP as .dag data (gunbc.roadmap_authority) — the markdown analogue of
ci.yml's authored data ci_workflow, the single authority the ROADMAP.md projection derives from.

Frame is the win: the frame is modelled (sections, nested checkbox forests via dependency edges,
sub-group labels, plan-doc pointers, PR bindings); pure prose (section intros, the ◆ Milestones
spine) is fenced verbatim as opaque authored Strings (the §5 DecodeFidelity fence), never modelled
into medium constructs.

Model evolution (subsumes the slice-2 single-list section, no fork §3)

• roadmap_model — SectionElement = Prose{content} | Group{label,nodes,edges}. A section is now an
  ordered element sequence (prose interleaved with labelled checkbox sub-groups). The old flat
  RoadmapSection{nodes,edges} is one Group{label:""}. Label is semantic text; the uniform
  **{label}:** frame is projection-owned (single authority).
• roadmap_emit — emit-refs-from-binding: a DerivableLine emits its (#N/#M) annotation from
  prs (§3); mentions keep refs in their AuthoredLine prose. Section projection folds elements in order.
• roadmap_document — RoadmapSection carries elements: List<SectionElement>.

The 6 status corrections (authored to MERGED REALITY)

• C1 measure rows (std.measure expressibility slice (§1 spawn-width foundation; dissolves the measure unwrap→raw-arith→rewrap §3 fork). Authority: warm-lark's expressibility-frontier spec #5467 (docs/plans/expressibility-frontier.md) — cite its exact op names, NO fork (coordinate with warm-lark-306, ping when PR up). #5470/std.measure demand-CEIL follow-up (§1 spawn-width; completes the ceil≠floor money-pair after #5470 landed the FLOOR family). Builds DIRECTLY on merged #5470 (measure.dag now has measure_scale_fraction_floor + measure_fit_count_floor). Authority: warm-lark's #5467 (docs/plans/expressibility-frontier. #5478) — were missing; now derived [x] in §1.
• C2 round-trip law (Emission slice: implement the §5.2 round-trip law (ingest-of-emit per medium) as the target-completeness acceptance test + per-medium decidability partition, per merged #5513/#5496 plan. First medium = markdown: a markdown INGEST reading the SAME serialize_markdown rows, proving ingest-of-emit green #5525/emission(§5.2): GHA-expression round-trip law — second medium-completeness oracle #5527) — its own [x] row, distinct from the medium-axis checkmark (no overclaim).
• C3 inversion sub-rows (Invert hand-maintained docs - generate ROADMAP from .dag authority plus drift-gate, starting with the PR-to-checkbox status slice #5491/ROADMAP slice-2 step-2: emit a section from the work-DAG model + §2 delete redundant box enum #5508/ROADMAP slice-2 step-3a: whole-document projection + pure golden witness #5520) — slice-1/2/step-3a; step-3b ROADMAP inversion slice-3b: fold CompletionBinding into RoadmapItem closed-sum (DerivableLine|AuthoredLine) #5529 deliberately not in the merged set.
• C4 self-host PATH-A — Route-A: class-3 corpus-global emit selector + cargo-green class-3-embodying v1-bundled seed (not §7 fixpoint) #5481 in the spine but §7 regen-fixpoint deferred (Stage0 regen lockstep re-repair: .dag authority + mirror sync (doc_reachability + 2 drifted hand-mods, bytes_identity_hash host-fn, advisory family) #5514), src/v1 NOT yet deletable.
• C5 edge-(b) rust-gate coverage — stays [ ] (scoped / pending greenlight; no status change).

Verification (green by execution)

All 5 roadmap witnesses true: status, model, emit, document, authority. The authority witness
proves the frame, the 6 corrections, emit-refs-from-binding, and the two ruling invariants — (a) prose
emits byte-verbatim incl internal markup, (b) ordered element interleaving — with a
perturbed-merged-set derivation discriminator and a reversed-order negative.

The effectful RoadmapGate (read ROADMAP.md + byte-compare) is deferred to a later increment
(checkpoint to the lane owner before it lands), per the lane design.

Notes

• Stacked on ROADMAP inversion slice-3b: fold CompletionBinding into RoadmapItem closed-sum (DerivableLine|AuthoredLine) #5529 (step-3b) until it merges. This branch is based on the step-3b RoadmapItem
  (DerivableLine|AuthoredLine), which is in ROADMAP inversion slice-3b: fold CompletionBinding into RoadmapItem closed-sum (DerivableLine|AuthoredLine) #5529, not yet on main — so the diff currently also shows the
  3b roadmap_status content. When ROADMAP inversion slice-3b: fold CompletionBinding into RoadmapItem closed-sum (DerivableLine|AuthoredLine) #5529 merges I rebase onto fresh main and that content drops out, leaving
  a clean transcription-only diff. Kept as a separate PR per the lane hygiene.
• The MODELING-COHERENCE check reported UNAVAILABLE due to a circular dependency + missing source-root
  in the checker's own ctrl/plans corpus (plans.coherence → plans.reducible → coherence.*, and a
  std.reducible resolution failure) — none of those modules exist in this repo; std.reducible resolves
  fine here. It is a checker-infra artifact, unrelated to these dsl/gunbc/roadmap_* changes.

🤖 Generated with Claude Code

[gunbai-bot]

#5529 (step-3b) has merged, so I merged fresh main into this branch — the 3b overlap reconciled and dropped out; the diff is now transcription-only (roadmap_authority + the SectionElement/emit-refs evolution + 3 tests). Conflicts in roadmap_emit/document_test/emit_test were resolved by taking this branch's superset (3b base + transcription). All 5 roadmap witnesses (status/model/emit/document/authority) re-verified green by execution post-merge; mergeable=MERGEABLE. Removed the now-obsolete [MERGE #5529 FIRST] title guard (the twin hazard is gone). The head bump stales the prior approval — re-review welcome. — sent from merry-deer-299