Editor starter-product checks

Every case here is a starter-product check, owned by docs/starter, not a Protocol tier. All existing byte-preservation and edit assertions remain in CI. Directories describe content; corpus-index.json determines each case’s single owner.

Compatible editors apply structured edits to a .uw.md file and produce a new .uw.md that:

• Round-trips formatting for unrelated regions (untouched bytes stay identical, ignoring trailing whitespace).
• Honors the supersede vs replace policy from BUILTIN_EDIT_POLICIES (UW_PROTOCOL.md Part V).
• Updates _meta provenance correctly (new version, timestamp, actor, etc.).
• Updates frontmatter last_modified on every write.

Fixtures

Each scenario lives in its own subdirectory:

fixtures/<scenario-id>/
├── before.uwx.md      Input file
├── operation.json    The EditOperation to apply
└── after.uwx.md       Expected output

Each scenario also includes a context.json describing the actor invoking the edit (source, agent_id, agent_version, actor) — required by the reference runner to populate _meta provenance.

Provided scenarios

Scenario	Operation	What it tests
frontmatter-set-recommendation	frontmatter_set of recommendation	Frontmatter update + last_modified bump
section-replace-property	section_replace of property (manual source)	In-place section replace per BUILTIN_EDIT_POLICIES (no supersede)
section-supersede-risk-rating	section_replace of risk_assessment (agent source)	Supersede chain: prior version flagged superseded: true, new version appended
gaps-section-update	frontmatter_set with options.json: {maintainGaps: true}	Post-write maintainer hook regenerates the gaps section under actor system/gaps-maintainer
parent-hash-stamp	section_supersede with options.json: {integrity: true} and context.json carrying parentHash	applyEditAsync recomputes content_hash and stamps parent_hash against the prior block's hash; content_hash is masked as <volatile> in baseline because canonicalization includes the timestamp
stale-parent-rejected	section_supersede with context.parentHash deliberately wrong	Negative-path fixture: expected-error.json asserts applyEditAsync rejects with INT-02

Optional fixture siblings

• context.json — EditContext (source, agent_id, agent_version, actor, optional parentHash).
• options.json — ApplyEditOptions ({integrity?: boolean, maintainGaps?: boolean, …}); when integrity: true the runner routes the edit through applyEditAsync.
• expected-error.json — {code, category} for negative-path fixtures. When present, the runner asserts the edit fails with that code instead of comparing against after.uwx.md.

A compatible starter editor's output for before.uwx.md + operation.json MUST match after.uwx.md after both files are normalized (stripping trailing whitespace, CRLF differences, and volatile fields: last_modified, _meta.provenance.timestamp, ts= fence attributes).

Run via:

node scripts/run-conformance.mjs --suite=starter-editor