Publish the resolved per-slot dose units and a slot-aware runway on the medication wire

A medication whose slots carry different doses (a whole tablet in the
morning, a half at noon — #219) was consumed correctly but reported
wrongly: the wire shipped only the raw nullable per-slot column (clients
had to derive the inheritance), stockDosesRemaining divided by the
medication-level units alone, and no runway figure existed outside the
low-stock push.

- Every schedule now carries resolvedUnitsPerDose, resolved server-side
  exactly like the intake consumption resolver.
- stockDosesRemaining divides the units pool by the schedule-weighted
  average units per dose.
- runwayDays (whole days of supply under the slot-aware burn rate) rides
  the list AND detail payloads; the detail GET also gains the stock
  aggregates the list already had.
- The low-stock engine runs the same slot-aware math, so the push and
  the wire cannot disagree; the web cards, table, and detail Übersicht
  prefer the server figure over their client estimate.
- OpenAPI regenerated with the new fields.

src/app/api/medications/[id]/glp1/route.ts

@@ -110,7 +110,12 @@ export const GET = apiHandler(
       prefsRow?.notificationPrefs ?? null,
       medication.reorderLeadDays,
     );
-    const schedules: RunwaySchedule[] = medication.schedules;
+    const schedules: RunwaySchedule[] = medication.schedules.map((sched) => ({
+      ...sched,
+      // Decimal → number so the slot-aware runway math reads the wire shape.
+      unitsPerDose:
+        sched.unitsPerDose === null ? null : Number(sched.unitsPerDose),
+    }));
     /** runway ≤ effective trigger AND the alert is enabled. */
     const isLowStock = (dosesRemaining: number): boolean => {
       if (runwayFloor === null) return false;

src/app/api/medications/[id]/route.ts

@@ -33,6 +33,10 @@ import {
   recomputeMedicationComplianceForDay,
 } from "@/lib/rollups/medication-compliance-rollups";
 import { assertMedicationOwnership } from "@/lib/medications/route-guards";
+import {
+  effectiveUnitsPerDose,
+  estimateUnitsRunwayDays,
+} from "@/components/medications/detail/supply-runway";
 import { serializeScheduleUnitsPerDose } from "@/lib/medications/schedule-units-dto";
 import { hhmmToMinutesOrNull } from "@/lib/medications/scheduling/hhmm";
 import { getUserTodayBounds } from "@/lib/tz/local-day";
@@ -177,13 +181,59 @@ export const GET = apiHandler(
       },
     });
 
+    // v1.37.19 — stock + runway on the detail wire, mirroring the list
+    // payload's semantics: NULL stock = inventory tracking off, 0 = the
+    // supply ran out; runwayDays via the slot-aware burn rate. Published
+    // resolved so no client re-derives the inheritance / cadence math.
+    const [usableStock, anyItemCount] = await Promise.all([
+      prisma.medicationInventoryItem.aggregate({
+        where: {
+          userId: user.id,
+          medicationId: id,
+          state: { in: ["ACTIVE", "IN_USE"] },
+          unitsRemaining: { gt: 0 },
+        },
+        _sum: { unitsRemaining: true },
+      }),
+      prisma.medicationInventoryItem.count({
+        where: { userId: user.id, medicationId: id },
+      }),
+    ]);
+    const schedulesDto = serializeScheduleUnitsPerDose(
+      medication.schedules,
+      medication.unitsPerDose,
+    );
+    const stockUnitsRemaining =
+      anyItemCount > 0 ? Number(usableStock._sum.unitsRemaining ?? 0) : null;
+    const stockDosesRemaining =
+      stockUnitsRemaining === null
+        ? null
+        : Math.floor(
+            stockUnitsRemaining /
+              effectiveUnitsPerDose(
+                schedulesDto,
+                Number(medication.unitsPerDose),
+              ),
+          );
+    const runwayDays =
+      stockUnitsRemaining === null
+        ? null
+        : estimateUnitsRunwayDays(
+            stockUnitsRemaining,
+            schedulesDto,
+            Number(medication.unitsPerDose),
+          );
+
     return apiSuccess({
       ...medication,
       unitsPerDose: Number(medication.unitsPerDose),
-      schedules: serializeScheduleUnitsPerDose(medication.schedules),
+      schedules: schedulesDto,
       category,
       nextDueAt: display ? display.at.toISOString() : null,
       nextDueOverdue: display?.overdue ?? false,
+      stockUnitsRemaining,
+      stockDosesRemaining,
+      runwayDays,
     });
   },
 );
@@ -836,7 +886,10 @@ export const PUT = apiHandler(
     return apiSuccess({
       ...medication,
       unitsPerDose: Number(medication.unitsPerDose),
-      schedules: serializeScheduleUnitsPerDose(medication.schedules),
+      schedules: serializeScheduleUnitsPerDose(
+        medication.schedules,
+        medication.unitsPerDose,
+      ),
       category: normalizedCategory,
     });
   },

src/app/api/medications/route.ts

@@ -95,7 +95,10 @@ async function respondWithExistingMirror(
     ...medication,
     unitsPerDose: Number(medication.unitsPerDose),
     // #219 — Decimal → number for the per-schedule column too.
-    schedules: serializeScheduleUnitsPerDose(medication.schedules),
+    schedules: serializeScheduleUnitsPerDose(
+      medication.schedules,
+      Number(medication.unitsPerDose),
+    ),
     category,
   });
 }
@@ -413,7 +416,10 @@ export const POST = apiHandler(async (request: NextRequest) => {
       ...medication,
       unitsPerDose: Number(medication.unitsPerDose),
       // #219 — Decimal → number for the per-schedule column too.
-      schedules: serializeScheduleUnitsPerDose(medication.schedules),
+      schedules: serializeScheduleUnitsPerDose(
+        medication.schedules,
+        medication.unitsPerDose,
+      ),
       category: normalizedCategory,
     },
     201,