fix(measurements): accept deviceType on single-entry POST (mirrors batch route)

`Measurement.deviceType` exists on the row, was added by the W8c
batch ingest path, but the single-entry `createMeasurementSchema`
omitted it — every single-row POST silently dropped the device tag
even when the client supplied one. Manual rows tagged with watch /
scale / ring metadata lost their attribution at the schema boundary
and showed up as unsourced.

Declare `deviceType` on the schema (optional, nullable, 1–32 chars),
thread it through both single-entry and array-body POST handlers,
and add three RTL cases (present, null, omitted) so the parsed
shape stays observable.

src/app/api/measurements/route.ts

@@ -96,6 +96,10 @@ async function postMeasurement(request: NextRequest) {
             notes: m.notes ?? null,
             glucoseContext:
               (m.glucoseContext as GlucoseContext | undefined) ?? null,
+            // v1.4.25 W10 reconcile (code-review M4): mirror the
+            // single-entry path so the multi-entry batch persists
+            // `deviceType` instead of silently dropping it.
+            deviceType: m.deviceType ?? null,
           },
         }),
       ),
@@ -127,7 +131,7 @@ async function postMeasurement(request: NextRequest) {
     return apiError(parsed.error.issues[0].message, 422);
   }
 
-  const { type, value, measuredAt, notes, source, glucoseContext } =
+  const { type, value, measuredAt, notes, source, glucoseContext, deviceType } =
     parsed.data;
 
   // Handle unique constraint violation
@@ -143,6 +147,11 @@ async function postMeasurement(request: NextRequest) {
         measuredAt,
         notes: notes ?? null,
         glucoseContext: (glucoseContext as GlucoseContext | undefined) ?? null,
+        // v1.4.25 W10 reconcile (code-review M4): the deviceType column
+        // already accepts client metadata from the batch route. Mirror
+        // the behaviour here so single-entry POST persists the tag
+        // instead of silently dropping it.
+        deviceType: deviceType ?? null,
       },
     });
   } catch (err) {

src/lib/validations/__tests__/measurement.test.ts

@@ -130,5 +130,47 @@ describe("measurement validation", () => {
       });
       expect(parsed.success).toBe(false);
     });
+
+    // v1.4.25 W10 reconcile (code-review M4): `deviceType` was a
+    // batch-only field; the single-entry schema silently dropped it.
+    // Now it parses through so the column is populated whether the
+    // client posts one row or many.
+    it("accepts an optional deviceType tag and surfaces it on the parsed value", () => {
+      const parsed = createMeasurementSchema.safeParse({
+        ...validBase,
+        type: "WEIGHT",
+        value: 82,
+        deviceType: "scale",
+      });
+      expect(parsed.success).toBe(true);
+      if (parsed.success) {
+        expect(parsed.data.deviceType).toBe("scale");
+      }
+    });
+
+    it("accepts a null deviceType so a client can explicitly clear the column", () => {
+      const parsed = createMeasurementSchema.safeParse({
+        ...validBase,
+        type: "WEIGHT",
+        value: 82,
+        deviceType: null,
+      });
+      expect(parsed.success).toBe(true);
+      if (parsed.success) {
+        expect(parsed.data.deviceType).toBeNull();
+      }
+    });
+
+    it("treats a missing deviceType as undefined (back-compat with pre-W10 clients)", () => {
+      const parsed = createMeasurementSchema.safeParse({
+        ...validBase,
+        type: "WEIGHT",
+        value: 82,
+      });
+      expect(parsed.success).toBe(true);
+      if (parsed.success) {
+        expect(parsed.data.deviceType).toBeUndefined();
+      }
+    });
   });
 });

src/lib/validations/measurement.ts

@@ -205,6 +205,14 @@ export const createMeasurementSchema = z
     // Only applies when type === BLOOD_GLUCOSE. Mirrored by a CHECK
     // constraint in Postgres (see migration 0021).
     glucoseContext: glucoseContextEnum.optional(),
+    // v1.4.25 W10 reconcile (code-review M4): the single-entry POST
+    // dropped `deviceType` silently because the column existed on
+    // `Measurement` and was accepted by the batch route, but never
+    // declared in this schema. iOS clients that POST one row at a
+    // time (and dashboards that backfill manual rows with device
+    // metadata) now persist the tag instead of seeing it disappear.
+    // Accepts `null` so a client can explicitly clear the column.
+    deviceType: z.string().min(1).max(32).nullable().optional(),
   })
   .refine((data) => validateMeasurementRange(data.type, data.value) === null, {
     message: "Value out of plausible range",