The consolidation program — one engine by extraction

[softmarshmallow]

The umbrella for the era after the v2 landing (#5): consolidating the legacy engine (crates/grida) and the v2 engine (crates/n0) into one engine by extraction — the successor program to the legacy seam program (#27).

The normative reference is the git-persisted program directory: docs/wg/consolidation/ — start at its index. The docs:

• index — start-here: reading order, the standing rules, working conventions
• goal — what n0 becomes (render CLIs, engine ecosystem, dev editor, render modes, format posture) and its non-goals
• topology — chassis vs know-how: the per-domain adoption map, render modes, the crate silhouette
• method — the step lifecycle, the three step shapes with worked examples, the gates
• glossary — the program vocabulary
• charter — the ratified route: phases 0–6 with entry/exit gates, the first three PRs, the owner decision registry, and the known unknowns

This issue tracks execution state (the position); the directory defines the program (the route).

Sequencing rule (binding on every PR in this program)

• Zero-behavior moves (crate cuts, re-exports) are gated by byte-identical sweeps alone — they never wait for the scoreboard.
• Capability-granting moves (n0 gaining an importer or any new rendering surface) are gated by the v1-vs-n0 scoreboard — no capability lands unmeasured.
• The conformance bar is the Chromium/consensus oracle, never v1 itself.
• Patrol-before-drop applies to every absorption step.

Milestones

• Phase 0 — Land + arm: model-v2: anchor — land the v2 engine as the crates/n0 family #5 merged --no-ff; CI arming PR (required checks: declared pixel-sweep subset, seam architecture tests, lock-additions-only, wasm build, CI-hosted v2 gate baselines); decision issues filed; the two long-pole docs lanes started (anchor-spec WG graduation, htmlcss font-provider study)
• Phase 1 — Vocabulary lane (∥ 2): cg crate cut (byte gates); paint-RFD conformance suite vs both engines + gap report; the two pinned RFD amendments ratified; D-C decided on evidence
• Phase 2 — Instrument lane (∥ 1): scoreboard v0 (enumerated intersection corpus, per-fixture triples + coverage), CI-hosted with bless flow and wall-clock budget; flip rule ratified before any score exists
• Phase 3 — SVG: the SVG import IR crate cut (name + math vocabulary decided at cut); n0 packer with the dependency-direction lock; legacy suites byte-identical; n0 SVG entry scores on the board
• Phase 4 — HTML + editor lanes (concurrent): htmlcss front-end extraction after its closed-set lock + font-provider decision; n0 from_styled adapter scored; D6 (editor-core ownership, The engine migration — history & the consolidation guideline (residue from gridaco/grida) #1) decided via the timeboxed spike
• Phase 5 — Format + text oracle: .grida→n0 converter over a pinned real-document corpus; v2 archive story decided; text-oracle identity decided at this boundary only
• Phase 6 — Flip + retirement: per-suite bar flips off the Phase-2 criterion; crates/grida contracts by subtraction; wasm switch + freeze-contract retirement coordinated with the product side

First three PRs

1. CI arming
2. cg crate cut (no n0 changes)
3. Scoreboard v0 (+ PR 4: the paint conformance suite)

Refs: #5 (the landing), #9 (v2 model tracking), #27 (predecessor), #1 (D6 context).

Execution log

• CI arming PR landed — ci(consolidation): arm permanent migration gates #46 merged as 182bb7f2; permanent gates and CI-owned n0 baselines are on main, and all post-merge push workflows are green.
• Required-check ruleset registration — the active main ruleset still contains only deletion and non-fast-forward protection; register consolidation gates / armed and canvas build / build as required checks.
• Decision-issue filing sweep — twelve dedicated trackers filed; no registry decision taken.
• Anchor-spec WG graduation lane
• htmlcss font-provider study lane
• cg crate cut landed — refactor(cg): extract shared vocabulary crate #59 merged as cdba65c0; crates/cg is the skia-free workspace crate, legacy retains grida::cg through a re-export, and the declared 65-fixture sweep is byte-identical. No n0 or frozen-surface change.

Decision tracker index

• Phase 1: AMD decision(AMD): ratify the paint-model amendments #47; D-C decision(D-C): choose cg adoption or law-equivalence mapping per leaf #48
• Phase 2: FLIP decision(FLIP): ratify the per-suite conformance-bar flip rule #49
• Phase 3: NAME decision(NAME): name the SVG import IR crate and choose its math vocabulary #50
• Phase 4: D-D decision(D-D): choose the htmlcss font-provider seam #51; D6 decision(D6): choose editor-core ownership #52
• Phase 5: D-H decision(D-H): choose the production text oracle #53; D-G(b) decision(D-G(b)): choose the v2 archive story #54; D-J decision(D-J): choose format stewardship #55
• Preview lane: D-K decision(D-K): choose the realtime-preview time model #56
• Phase 6: D-E decision(D-E): govern per-suite conformance-bar flips #57; D-I decision(D-I): switch the wasm package and retire the freeze contract #58
• Already taken: GO at model-v2: anchor — land the v2 engine as the crates/n0 family #5
• Sequencing declaration: the consolidation follow-up order is already recorded on anchor — the v2 node model #9.