fix(series): bucket heart-rate variability and blood oxygen like pulse

The dense rule in /api/measurements/series covered pulse and glucose
only. Heart-rate variability and blood oxygen read every raw row for
any window up to 3650 days, and a watch or ring that writes them every
minute makes that the same unbounded read pulse had.

Both kinds now fold per local day beyond 90 days and per local hour
inside 90 days once the window holds more than 10 000 readings. A
bucket keeps the point shape of its kind: only pulse carries
valueMin / valueMax. Statistics stay computed over every reading, and
a sparse series inside 90 days is unchanged. The OpenAPI description
names the four kinds.

src/app/api/measurements/series/route.ts

@@ -49,11 +49,23 @@ const SLEEP_SERIES_MAX_DAYS = 365;
  * byte-identical. Sparse kinds (weight, BP, …) are untouched.
  */
 const DENSE_SERIES_RAW_WINDOW_DAYS = 90;
-const DENSE_SERIES_KINDS: ReadonlySet<string> = new Set(["glucose", "pulse"]);
+/**
+ * The kinds a device can write at sampling rate. Heart-rate variability and
+ * blood oxygen joined pulse and glucose once watches and rings began writing
+ * them every few minutes overnight: their 3650-day "Alle" range read every
+ * raw row, which is the read this rule exists to stop.
+ */
+const DENSE_SERIES_KINDS: ReadonlySet<string> = new Set([
+  "glucose",
+  "pulse",
+  "heartRateVariability",
+  "oxygenSaturation",
+]);
 
 /**
- * #1023 — inside the raw window, a pulse or glucose series with more rows
- * than this is bucketed per local hour in SQL instead of sent raw.
+ * #1023 — inside the raw window, a dense-kind series (pulse, glucose, HRV,
+ * blood oxygen) with more rows than this is bucketed per local hour in SQL
+ * instead of sent raw.
  *
  * A watch that records heart rate once a minute puts 43 000 rows in the
  * default 30-day window and 130 000 in 90 days: a 15 MB response the client
@@ -381,7 +393,7 @@ export const GET = apiHandler(async (request: NextRequest) => {
         },
       })) > DENSE_SERIES_RAW_ROW_CAP)
   ) {
-    // Day buckets past the raw window; hour buckets for a pulse or CGM
+    // Day buckets past the raw window; hour buckets for a dense-kind
     // stream too dense to send raw inside it.
     const grain = days > DENSE_SERIES_RAW_WINDOW_DAYS ? "day" : "hour";
     // v1.28.25 — long-window read of a sample-dense kind (CGM glucose,
@@ -489,17 +501,19 @@ export const GET = apiHandler(async (request: NextRequest) => {
         };
       }
     } else {
-      // pulse — `value` is the bucket's average; valueMin/valueMax carry the
-      // bucket's low/high band (folding each hourly import bucket's own
+      // `value` is the bucket's average. For pulse, valueMin/valueMax carry
+      // the bucket's low/high band (folding each hourly import bucket's own
       // spread via the COALESCE above), same band semantics as the per-hour
-      // shape.
+      // shape. The other dense kinds keep the bare point shape their raw rows
+      // have, so a client reads a bucket the way it reads a reading.
       points = bucketRows.map((r) => ({
         id: dayId(r.bucket_start),
         at: r.bucket_start.toISOString(),
         value: round2(r.mean),
         secondary: null,
-        valueMin: r.min_value,
-        valueMax: r.max_value,
+        ...(kind === "pulse"
+          ? { valueMin: r.min_value, valueMax: r.max_value }
+          : {}),
       }));
       if (
         rawAgg !== undefined &&

src/lib/openapi/routes/measurements.ts

@@ -696,7 +696,7 @@ const seriesPointSchema = z.object({
   id: z
     .string()
     .describe(
-      "Measurement row id; `sleep:<wake-day>` for a sleep night; `day:<local-day>` for a day bucket (`pulse` / `glucose` beyond 90 days); `hour:<ISO start>` for an hour bucket (`pulse` / `glucose` within 90 days when the window holds more than 10 000 readings).",
+      "Measurement row id; `sleep:<wake-day>` for a sleep night; `day:<local-day>` for a day bucket (`pulse`, `glucose`, `heartRateVariability`, `oxygenSaturation` beyond 90 days); `hour:<ISO start>` for an hour bucket (the same kinds within 90 days when the window holds more than 10 000 readings).",
     ),
   at: z.iso.datetime({ offset: true }).describe("Point timestamp (ISO-8601)."),
   value: z.number().describe("Primary value in the top-level `unit`."),
@@ -751,7 +751,7 @@ const seriesResponse = z
   .meta({
     id: "MeasurementsSeriesResponse",
     description:
-      "iOS-friendly per-kind time series: one point per reading (or per reconstructed night for `sleep`), an explicit `unit` token, and a summary `stats` block. Sample-dense kinds are bucketed server-side: `pulse` and `glucose` beyond 90 days per local day, and `pulse` / `glucose` within 90 days per local hour when the window holds more than 10 000 readings (a continuous glucose sensor, a watch recording heart rate every minute; a cuff or fingerstick meter stays raw). A bucket carries the mean as `value`; a `pulse` bucket also carries its range as `valueMin` / `valueMax`, and a `glucose` bucket is converted to the user's unit like a raw reading. `stats` is always computed over the underlying readings, never over the buckets.",
+      "iOS-friendly per-kind time series: one point per reading (or per reconstructed night for `sleep`), an explicit `unit` token, and a summary `stats` block. Sample-dense kinds (`pulse`, `glucose`, `heartRateVariability`, `oxygenSaturation`) are bucketed server-side: beyond 90 days per local day, and within 90 days per local hour when the window holds more than 10 000 readings (a continuous glucose sensor, a watch or ring recording every minute; a cuff, a fingerstick meter or a few readings a night stay raw). A bucket carries the mean as `value` and otherwise has the shape of a reading of its kind; a `pulse` bucket also carries its range as `valueMin` / `valueMax`, and a `glucose` bucket is converted to the user's unit like a raw reading. `stats` is always computed over the underlying readings, never over the buckets.",
   });
 
 // ── Batched daily series (v1.18.6 dashboard fetch coalescing) ────────