refactor(methods): rename family-page feed filter param ?cellLine= → ?entity= (#1234)

The Surface B master-detail feed filter on the method-family page was keyed
on ?cellLine=, accurate while every entity was a cell line. As the entity
layer broadens past cell lines (ReciterAI #252), the generic ?entity= key
is the right contract. Renames the 8 read/write sites (rail set/delete,
feed get/set/clear, route validation) plus the doc-comments that document
the key. No backward-compat shim: the entity layer is staging-only / prod-off
with no external deep-links. Internal cellLine* identifiers are left as-is
(no behavior change; out of scope for a URL-param rename).

Author: paulalbert1

app/(public)/methods/[supercategory]/[family]/page.tsx

@@ -93,7 +93,7 @@ export default async function FamilyPage({
 
   // #1166 — when the family resolves to specific cell lines, the master-detail
   // cell-line rail (Surface B §5.1) sits in the left column of the publications
-  // section, driving the `?cellLine=` feed filter. When there are no cell lines,
+  // section, driving the `?entity=` feed filter. When there are no cell lines,
   // the publications feed renders without the rail.
   const hasCellLines = cellLineEntities.length > 0;
   const cellLineLabels = Object.fromEntries(cellLineEntities.map((e) => [e.entityId, e.label]));
@@ -232,7 +232,7 @@ export default async function FamilyPage({
       <section id="publications" className="scroll-mt-20">
         {hasCellLines ? (
           // #1166 Surface B — master-detail: the cell-line rail (left) drives the
-          // shared `?cellLine=` filter the feed (right) reads. Mirrors the
+          // shared `?entity=` filter the feed (right) reads. Mirrors the
           // supercategory layout's sticky-rail + cornell-red divider for parity.
           <div className="mt-16">
             <hr className="mb-10 border-border" />

app/api/methods/[supercategory]/[family]/publications/route.ts

@@ -106,9 +106,9 @@ export async function GET(
   // #1166 Surface B — optional cell-line filter. Validated against the opaque-id
   // shape; the loader additionally gates it on METHODS_LENS_CELL_LINE_ENTITIES and
   // ignores an unknown id (empty feed), so a bad value is a 400 here, never a leak.
-  const entityIdRaw = sp.get("cellLine");
+  const entityIdRaw = sp.get("entity");
   if (entityIdRaw !== null && !ENTITY_ID_RE.test(entityIdRaw)) {
-    return apiError("invalid cellLine", 400);
+    return apiError("invalid entity", 400);
   }
   const entityId = entityIdRaw ?? undefined;
 

components/method/cell-line-rail.tsx

@@ -4,7 +4,7 @@
  * #1166 Surface B — the master-detail cell-line rail on the method-family page, the
  * left column of the publications master-detail (the family-page analog of the
  * supercategory `FamilyRail`). Lists the specific cell lines the family resolves to,
- * usage_count-desc; selecting one sets the shared `?cellLine=<entityId>` filter that
+ * usage_count-desc; selecting one sets the shared `?entity=<entityId>` filter that
  * the publication feed reads (spec §6 — one shared, singular filter). No "All" row:
  * no selection ⇒ the full family list (the feed's default); clicking the active row
  * clears the filter back to the full list.
@@ -26,7 +26,7 @@ export function CellLineRail({ entities }: { entities: CellLineEntity[] }) {
   const pathname = usePathname();
   const searchParams = useSearchParams();
 
-  const active = searchParams.get("cellLine");
+  const active = searchParams.get("entity");
 
   // #1168 — the rail noun comes from the family's dominant entity kind (all
   // entities in a family share it), so a reagent/instrument/dataset family reads
@@ -36,8 +36,8 @@ export function CellLineRail({ entities }: { entities: CellLineEntity[] }) {
 
   const onSelect = (id: string | null) => {
     const params = new URLSearchParams(searchParams.toString());
-    if (id === null) params.delete("cellLine");
-    else params.set("cellLine", id);
+    if (id === null) params.delete("entity");
+    else params.set("entity", id);
     // Reset the feed to page 1 on a filter change (mirrors the prior strip).
     params.delete("page");
     const qs = params.toString();

components/method/family-publication-layout.tsx

@@ -39,15 +39,15 @@ export function FamilyPublicationLayout({
   supercategorySlug: string;
   familySegment: string;
   familyLabel: string;
-  /** #1166 — entity id → label for the feed's `?cellLine=` context-bar chip. */
+  /** #1166 — entity id → label for the feed's `?entity=` context-bar chip. */
   cellLineLabels?: Record<string, string>;
   /** #1166 — when the layout is the RIGHT column of the family-page master-detail,
    *  the page supplies its own `mt-16`+`<hr>` wrapper, so suppress this one's to
    *  avoid a stray rule above the feed inside the grid. */
   embedded?: boolean;
 }) {
   const feed = (
-    // The feed reads `?cellLine=` via useSearchParams (#1166) — Suspense lets the
+    // The feed reads `?entity=` via useSearchParams (#1166) — Suspense lets the
     // static shell emit and hydrate at request time (parity with the type-B layout).
     <Suspense fallback={null}>
       <FamilyPublicationFeed

components/method/publication-feed.tsx

@@ -65,7 +65,7 @@ type Hit = {
     isLast: boolean;
   }>;
   /** #1166/#1168 — the per-(pub × entity) relevance sentence, present only when the
-   *  feed is filtered by an entity (`?cellLine=`); revealed under the row. `usage`
+   *  feed is filtered by an entity (`?entity=`); revealed under the row. `usage`
    *  (WS-C #253) drives the badge: "appears" for a generic mention, else "used". */
   entityUsage?: {
     sentence: string;
@@ -95,7 +95,7 @@ export function FamilyPublicationFeed({
   familySegment: string;
   /** Resolved family label, used for the feed heading. */
   familyLabel: string;
-  /** #1166 — entity id → display label, so the `?cellLine=` context-bar chip can
+  /** #1166 — entity id → display label, so the `?entity=` context-bar chip can
    *  name the active cell line. Absent (or unknown id) ⇒ no cell-line filter UI. */
   cellLineLabels?: Record<string, string>;
 }) {
@@ -104,7 +104,7 @@ export function FamilyPublicationFeed({
   const searchParams = useSearchParams();
   // #1166 — the shared, URL-addressable cell-line filter (spec §6). Only honored
   // when its label is known (the entity belongs to this family + the flag is on).
-  const cellLineId = searchParams.get("cellLine");
+  const cellLineId = searchParams.get("entity");
   const cellLine = cellLineId && cellLineLabels?.[cellLineId] ? cellLineId : null;
   const cellLineLabel = cellLine ? cellLineLabels![cellLine] : null;
 
@@ -143,7 +143,7 @@ export function FamilyPublicationFeed({
 
   const clearCellLine = () => {
     const params = new URLSearchParams(searchParams.toString());
-    params.delete("cellLine");
+    params.delete("entity");
     params.delete("page");
     router.replace(params.toString() ? `${pathname}?${params.toString()}` : pathname, {
       scroll: false,
@@ -405,7 +405,7 @@ function useFeedFetch({
     url.searchParams.set("sort", sort);
     url.searchParams.set("page", String(page));
     url.searchParams.set("filter", filter);
-    if (cellLine) url.searchParams.set("cellLine", cellLine);
+    if (cellLine) url.searchParams.set("entity", cellLine);
 
     fetch(url.toString())
       .then((r) => {