fix(workouts): sanitize WHOOP zone enrichment

src/lib/measurements/__tests__/pick-canonical-workout-rows.test.ts

@@ -89,7 +89,11 @@ describe("pickCanonicalWorkoutRows", () => {
       avgHeartRate: 146,
       maxHeartRate: 181,
       metadata: {
-        zoneDurations: { zone_one_milli: 60_000 },
+        zoneDurations: {
+          zone_one_milli: 60_000,
+          nestedSecret: { mustNotFlow: true },
+          zone_six_milli: 90_000,
+        },
         whoopWorkoutStrain: 12.3,
       },
     };
@@ -107,6 +111,11 @@ describe("pickCanonicalWorkoutRows", () => {
         zoneDurations: { zone_one_milli: 60_000 },
       },
     });
+    expect(
+      (picked.metadata as Record<string, unknown>).zoneDurations,
+    ).toEqual({
+      zone_one_milli: 60_000,
+    });
     expect(picked.metadata).not.toHaveProperty("whoopWorkoutStrain");
     expect(apple).toEqual({
       id: "apple",
@@ -149,6 +158,32 @@ describe("pickCanonicalWorkoutRows", () => {
     });
   });
 
+  it("rejects malformed WHOOP zone durations instead of partially copying them", () => {
+    const result = pickCanonicalWorkoutRows<RowFixture>([
+      {
+        id: "apple",
+        startedAt: new Date("2026-06-03T06:30:00Z"),
+        sportType: "running",
+        source: "APPLE_HEALTH",
+        metadata: { owner: "apple" },
+      },
+      {
+        id: "whoop",
+        startedAt: new Date("2026-06-03T06:30:30Z"),
+        sportType: "running",
+        source: "WHOOP",
+        metadata: {
+          zoneDurations: {
+            zone_one_milli: 60_000,
+            zone_two_milli: -1,
+          },
+        },
+      },
+    ]);
+
+    expect(result[0].metadata).toEqual({ owner: "apple" });
+  });
+
   it("does not enrich across sport or fixed-window boundaries", () => {
     const apple: RowFixture = {
       id: "apple",

src/lib/measurements/pick-canonical-workout-rows.ts

@@ -77,13 +77,43 @@ function jsonRecord(value: unknown): Record<string, unknown> | null {
     : null;
 }
 
+const WHOOP_ZONE_DURATION_KEYS = [
+  "zone_zero_milli",
+  "zone_one_milli",
+  "zone_two_milli",
+  "zone_three_milli",
+  "zone_four_milli",
+  "zone_five_milli",
+] as const;
+
+function sanitizedWhoopZoneDurations(
+  metadata: unknown,
+): Record<string, number> | null {
+  const raw = jsonRecord(jsonRecord(metadata)?.zoneDurations);
+  if (!raw) return null;
+
+  const sanitized: Record<string, number> = {};
+  for (const key of WHOOP_ZONE_DURATION_KEYS) {
+    const value = raw[key];
+    if (value === undefined) continue;
+    if (
+      typeof value !== "number" ||
+      !Number.isFinite(value) ||
+      value < 0
+    ) {
+      return null;
+    }
+    sanitized[key] = value;
+  }
+  return Object.keys(sanitized).length > 0 ? sanitized : null;
+}
+
 function enrichFromWhoopTwin<T extends WorkoutPickerRow>(
   winner: T,
   donor: T,
 ): T {
   const winnerMetadata = jsonRecord(winner.metadata);
-  const donorMetadata = jsonRecord(donor.metadata);
-  const donorZones = donorMetadata?.zoneDurations;
+  const donorZones = sanitizedWhoopZoneDurations(donor.metadata);
   const needsZones =
     donorZones != null && winnerMetadata?.zoneDurations == null;
   const needsAvg =