refactor(workouts): rename write-time picker to dedupeWorkoutBatch

The v1.4.42 W5 helper shipped under the same identifier
`pickCanonicalWorkoutRows` as the v1.4.30 read-time picker in
`src/lib/measurements/`. Same name in two modules with different
signatures (write-time takes no user-priority, read-time does) sets
up the next contributor to auto-complete the name in a new route
and silently invoke the wrong picker — no user-priority resolution
on a read, missing the 90-second window on a write.

Rename to `dedupeWorkoutBatch` so the write-time contract is
self-describing. The read-time picker keeps its established name.
One file's export + 12-case test suite + the batch-route caller
update — no algorithm change.

src/app/api/workouts/batch/route.ts

@@ -68,7 +68,7 @@ import {
   createBatchWorkoutSchema,
   MAX_WORKOUTS_PER_BATCH,
 } from "@/lib/validations/workout";
-import { pickCanonicalWorkoutRows } from "@/lib/workouts/canonical-rows";
+import { dedupeWorkoutBatch } from "@/lib/workouts/canonical-rows";
 import { Prisma, type MeasurementSource } from "@/generated/prisma/client";
 
 // v1.4.25 W16c — push-suppression threshold for workout PRs. A batch
@@ -270,7 +270,7 @@ async function postBatch(request: NextRequest): Promise<Response> {
   // dropped here surface to the iOS client as `duplicate` so the
   // sync cursor advances past them identically to the externalId
   // case below.
-  const canonicalPrepared = pickCanonicalWorkoutRows(
+  const canonicalPrepared = dedupeWorkoutBatch(
     prepared.map((p) => ({
       userId: p.row.userId,
       activityType: p.row.sportType,

src/lib/workouts/__tests__/canonical-rows.test.ts

@@ -12,7 +12,7 @@
 import { describe, expect, it } from "vitest";
 
 import {
-  pickCanonicalWorkoutRows,
+  dedupeWorkoutBatch,
   WORKOUT_DEDUP_WINDOW_MS,
   type WorkoutRow,
 } from "../canonical-rows";
@@ -37,9 +37,9 @@ function row(partial: Partial<TestRow> & { id: string }): TestRow {
   };
 }
 
-describe("pickCanonicalWorkoutRows", () => {
+describe("dedupeWorkoutBatch", () => {
   it("returns an empty array on empty input", () => {
-    expect(pickCanonicalWorkoutRows([])).toEqual([]);
+    expect(dedupeWorkoutBatch([])).toEqual([]);
   });
 
   it("collapses exact duplicates from the same source", () => {
@@ -61,7 +61,7 @@ describe("pickCanonicalWorkoutRows", () => {
       createdAt: new Date("2026-05-21T08:31:00Z"),
     });
 
-    const out = pickCanonicalWorkoutRows([a, b]);
+    const out = dedupeWorkoutBatch([a, b]);
     expect(out).toHaveLength(1);
     // Same calories → earliest createdAt wins (`a`).
     expect(out[0]!.id).toBe("a");
@@ -85,7 +85,7 @@ describe("pickCanonicalWorkoutRows", () => {
       caloriesKcal: 500,
     });
 
-    const out = pickCanonicalWorkoutRows([apple, withings]);
+    const out = dedupeWorkoutBatch([apple, withings]);
     expect(out).toHaveLength(1);
     // Source-axis wins outright — APPLE_HEALTH beats WITHINGS even
     // when WITHINGS has higher calories. The calories tie-break only
@@ -106,7 +106,7 @@ describe("pickCanonicalWorkoutRows", () => {
       startedAt: new Date("2026-05-21T08:10:00Z"),
     });
 
-    const out = pickCanonicalWorkoutRows([first, second]);
+    const out = dedupeWorkoutBatch([first, second]);
     expect(out.map((r) => r.id)).toEqual(["first", "second"]);
   });
 
@@ -125,7 +125,7 @@ describe("pickCanonicalWorkoutRows", () => {
       startedAt: new Date("2026-05-21T08:00:00Z"),
     });
 
-    const out = pickCanonicalWorkoutRows([u1, u2]);
+    const out = dedupeWorkoutBatch([u1, u2]);
     expect(out.map((r) => r.id).sort()).toEqual(["u1", "u2"]);
   });
 
@@ -144,7 +144,7 @@ describe("pickCanonicalWorkoutRows", () => {
       startedAt: new Date("2026-05-21T08:00:00Z"),
     });
 
-    const out = pickCanonicalWorkoutRows([walk, strength]);
+    const out = dedupeWorkoutBatch([walk, strength]);
     expect(out.map((r) => r.id).sort()).toEqual(["strength", "walk"]);
   });
 
@@ -173,12 +173,12 @@ describe("pickCanonicalWorkoutRows", () => {
     });
 
     // Pair 1: hi vs lo → hi wins on calories.
-    expect(pickCanonicalWorkoutRows([lo, hi]).map((r) => r.id)).toEqual(["hi"]);
+    expect(dedupeWorkoutBatch([lo, hi]).map((r) => r.id)).toEqual(["hi"]);
 
     // Pair 2: hi vs lo-early → hi STILL wins because calories trump
     // createdAt.
     expect(
-      pickCanonicalWorkoutRows([loWithEarlierCreated, hi]).map((r) => r.id),
+      dedupeWorkoutBatch([loWithEarlierCreated, hi]).map((r) => r.id),
     ).toEqual(["hi"]);
   });
 
@@ -198,7 +198,7 @@ describe("pickCanonicalWorkoutRows", () => {
       createdAt: new Date("2026-05-21T08:45:00Z"),
     });
 
-    expect(pickCanonicalWorkoutRows([late, early]).map((r) => r.id)).toEqual([
+    expect(dedupeWorkoutBatch([late, early]).map((r) => r.id)).toEqual([
       "early",
     ]);
   });
@@ -211,13 +211,13 @@ describe("pickCanonicalWorkoutRows", () => {
     const first = row({ id: "first", source: "MANUAL" });
     const second = row({ id: "second", source: "MANUAL" });
 
-    expect(pickCanonicalWorkoutRows([first, second]).map((r) => r.id)).toEqual([
+    expect(dedupeWorkoutBatch([first, second]).map((r) => r.id)).toEqual([
       "first",
     ]);
     // Reversed input → reversed survivor. Confirms the tie-breaker
     // genuinely consults input order rather than a hidden field
     // (e.g. `id` lexicographic).
-    expect(pickCanonicalWorkoutRows([second, first]).map((r) => r.id)).toEqual([
+    expect(dedupeWorkoutBatch([second, first]).map((r) => r.id)).toEqual([
       "second",
     ]);
   });
@@ -247,12 +247,12 @@ describe("pickCanonicalWorkoutRows", () => {
 
     // anchor + onBoundary → one group; APPLE_HEALTH wins.
     expect(
-      pickCanonicalWorkoutRows([anchor, onBoundary]).map((r) => r.id),
+      dedupeWorkoutBatch([anchor, onBoundary]).map((r) => r.id),
     ).toEqual(["anchor"]);
 
     // anchor + justOutside → two distinct groups, both survive.
     expect(
-      pickCanonicalWorkoutRows([anchor, justOutside]).map((r) => r.id),
+      dedupeWorkoutBatch([anchor, justOutside]).map((r) => r.id),
     ).toEqual(["anchor", "outside"]);
   });
 
@@ -275,7 +275,7 @@ describe("pickCanonicalWorkoutRows", () => {
       }),
     );
 
-    expect(pickCanonicalWorkoutRows(rows).map((r) => r.id)).toEqual([
+    expect(dedupeWorkoutBatch(rows).map((r) => r.id)).toEqual([
       "APPLE_HEALTH",
     ]);
   });
@@ -287,7 +287,7 @@ describe("pickCanonicalWorkoutRows", () => {
     const a = row({ id: "a", source: "APPLE_HEALTH", caloriesKcal: 100 });
     const b = row({ id: "b", source: "WITHINGS", caloriesKcal: 100 });
     const before = JSON.stringify([a, b]);
-    pickCanonicalWorkoutRows([a, b]);
+    dedupeWorkoutBatch([a, b]);
     expect(JSON.stringify([a, b])).toBe(before);
   });
 });

src/lib/workouts/canonical-rows.ts

@@ -14,8 +14,12 @@
  *     filters the read result so the dashboard tile shows one row per
  *     logical workout.
  *
- *   - This helper (v1.4.42) — WRITE-time picker invoked by
- *     `POST /api/workouts/batch` BEFORE `prisma.workout.createMany`.
+ *   - This helper (`dedupeWorkoutBatch`, v1.4.42) — WRITE-time picker
+ *     invoked by `POST /api/workouts/batch` BEFORE
+ *     `prisma.workout.createMany`. The name intentionally diverges
+ *     from the read-time picker to make the auto-completion path
+ *     unambiguous (write-time payload-internal dedup vs. read-time
+ *     cross-batch dedup with user-priority resolution).
  *     The v1.5 iOS sprint will ingest `HKWorkoutType` data in batches
  *     against `/api/workouts/batch`; Apple Watch + Withings ScanWatch
  *     paired to the same iPhone frequently capture the same workout
@@ -189,7 +193,7 @@ function compareCandidates<T extends WorkoutRow>(a: T, b: T): number {
  * within-window-of-neighbour rows. This is O(n²) worst case but
  * a typical batch is ≤ 100 entries so the constant is fine.
  */
-export function pickCanonicalWorkoutRows<T extends WorkoutRow>(
+export function dedupeWorkoutBatch<T extends WorkoutRow>(
   rows: readonly T[],
 ): T[] {
   if (rows.length === 0) return [];