Story-2359: Governing law becomes editable

Governing law is the list of acts and statutes a matter actually runs on — the Arbitration and Conciliation Act, a state stamp act, a contract's chosen law. It sits in the Brief's Case particulars rail, and until this change it was a wall: Vega read it out of the documents, joined it with ·, and printed it. If the framer misread a statute, or missed one, counsel had no way to say so. The most load-bearing legal fact on the page was the one nobody could touch.

This Story is pure reuse. Story-2355 built EditableList and put Key instruments on it; Story-2360 put three more lists on it. Governing law is the fifth consumer. No new primitive, no new editor, no new data path, no pnpm codegen, no backend change.

The gate that had to pass first

A field is only worth making editable if the write path will actually accept it. The frame edit endpoint (PATCH …/frame) declares fields as a free-form object in OpenAPI — additionalProperties: true — so the OpenAPI mirror alone cannot answer the question. The real allowlist is enforced server-side, in pramaan-functions:

src/domains/matter_frame/frame_contract.py

_META_FIELDS = frozenset({"frame_status", "missing_core_fields"})
EDITABLE_FRAME_FIELDS = frozenset(FrameMirror.model_fields) - _META_FIELDS

Every FrameOutput field except Vega's two honesty-gate meta fields is editable. governing_law is neither of those, and it carries exactly the shape key_instruments already proved:

What changed on the page

Counsel clicks an act, the caret drops in, blur commits. Clearing an act's text removes the row — the row IS the value, so an empty row is no row. "Add an act or statute" opens a fresh row. Every commit sends the whole next array, because the frame edit contract is full-value-per-field.

What was inherited, not rebuilt

• Optimism and rollback. The edit lands in the UI the instant counsel commits it; useAppEditMatterFrame's onMutate patches the cached Brief, onError restores the snapshot and toasts, onSettled reconciles with server truth. Zero new mutation code in this diff.
• Provenance. Each act carries the shared EditableSurface marker via itemProvenance={(act) => fieldProvenance(brief, "governing_law")} — the same call the old glyph made, now per row instead of per line. A canonical or locked value stays un-removable; that gate lives in the primitive.
• Motion. Add/remove/reorder animate through AnimatedList, which EditableList already wraps.
• Copy. Two new keys in both locales: addLaw and lawPlaceholder. The primitive holds no copy; the caller resolves every label.

The dead code that went with it

Visual density preserved

The rail is dense on purpose — it is a reference card, not a form. The promoted block keeps the rail's shape: the same FieldLabel eyebrow, the same mb-4 block rhythm, the same Divider above and below, and the same EditableList density Key instruments established two rows down. The only visual delta is deliberate and is the point of the Story: acts stack as rows instead of running together on one ·-joined line, which is what makes each one individually correctable.

Storybook

No new story. Governing law exercises states the Shared/EditableList catalog already demonstrates — Populated, Empty/add-first, Add flow, Remove, Provenance-marked, Rollback on error. No genuinely new state emerged, so no new catalog entry was earned.

Verification