E-D (layout-ir, honest solver tier): add SolverTier::Stub (a non-conformance rung
below Minimal) and have StubSolver report it instead of falsely claiming the
Minimal conformance tier; the passthrough evaluates no constraints and computes
no quality metrics.
E-C (layout-ir, constraint/reference validation): ConstrainedLayoutIR::validate()
now also checks the LayoutConstraint vector — NoCollision/Align/PositionWithin
must name glyphs in the set, SystemBreakAt/PageBreakAt must name existing slots,
PositionWithin regions must be finite/non-negative — rejecting dangling
references instead of silently accepting them.
E-B (layout-ir, content-sensitive ScoreVersion): derive ScoreVersion from the
whole score's canonical bytes (Agent B's whole-score codec) rather than the
layout projection's object identities, so a pure content edit that changes no
identifier still changes the version — required for correct incremental-layout
cache invalidation.
D-A (bundle, extension-root preservation): Bundle::commit now enforces
preservation — after the builder closure runs, every prior extension declaration
it did not re-declare (by extension_id) is carried forward verbatim, so an
extension-unaware writer cannot silently orphan an unknown extension's
preserved_chunk_roots. An extension-aware writer that re-declares its id keeps
control.
Each fix has a regression test; per-crate DECISIONS updated. (Item-6 remainder:
D-B operation-block summaries next; E-A real time-axis deferred per request.)
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Implements Agent E per spec/QUICKSTART.md — the layout intermediate
representation (Chapter 7) and the constraint-solver interface (Chapter 9):
* Four IR stages: LogicalLayoutIR -> ConstrainedLayoutIR ->
ResolvedLayoutIR -> RenderIR (interface only), with the composite-object
taxonomy, spring slots/constraints, vertical-band model, pages/systems,
engraving decisions + overrides, and the incremental dependency/cache model.
* TimeAxisModel tagged enum (Metric/Proportional/Aleatoric/Registered).
* Provenance back-references with manifestation- and synthesis-aware ids
((source, region) and (source, kind, ordinal)), so multiply-manifested and
synthesized objects never collide.
* In-tree Bravura GlyphCatalog (Send+Sync, metrics + render-data interface),
MUSCFNTM-tagged metrics hash with anchors hashed as a name-keyed map.
* Edit-barrier types keyed on OperationKindTag, with precise EditContext /
EditOracle scope/condition evaluation.
* StubSolver: returns SolveStatus::Solved with the input geometry verbatim;
spec-compliant SolveReport, Minimal tier + all-worst (unmeasured) metric
vector (no false conformance claim); rejects ill-formed input.
* f32 staff-space IR coordinates, quantized to the 1/1024 grid only at
canonical ResolvedLayoutIR serialization (Appendix D); non-finite geometry
is rejected, not normalized. Canonical encoding is injective in glyph
identity, provenance, engraving decisions, and catalog identity.
Re-points Agent F's testkit layout harness from its in-tree stub to the real
crate (v0 acceptance criterion 6) and expands its generators to E's public
surface. Expands Agent C's OperationKindTag to the full normative variant set
so edit barriers can prohibit every operation class.
Workspace gates green: fmt, clippy -D warnings, 377 tests, doc tests, rustdoc
-D warnings, and the conformance suite at scale 1. Decisions and Pass 11
candidates recorded in crates/epiphany-layout-ir/DECISIONS.md.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Levi Neuwirth