fix: unify stock semantics across planner and scheduler (#245)

* fix: unify stock semantics across planner and scheduler

* fix: stabilize dashboard hmr and align stock helper tests

frontend/src/utils/stock.ts

@@ -0,0 +1,43 @@
+import type { Medication } from "../types";
+
+export type BlisterStockSplit = {
+	fullBlisters: number;
+	openBlisterPills: number;
+	loosePills: number;
+};
+
+/**
+ * Split current blister stock into sealed full blisters, open blister pills,
+ * and loose pills using the configured loose-tablets baseline.
+ */
+export function splitCurrentBlisterStock(
+	currentPills: number,
+	pillsPerBlister: number,
+	configuredLooseTablets: number
+): BlisterStockSplit {
+	if (pillsPerBlister <= 0 || pillsPerBlister === 1) {
+		return { fullBlisters: 0, openBlisterPills: 0, loosePills: Math.max(0, currentPills) };
+	}
+
+	const safeCurrent = Math.max(0, currentPills);
+	const loosePills = Math.min(safeCurrent, Math.max(0, configuredLooseTablets));
+	const sealedPills = Math.max(0, safeCurrent - loosePills);
+
+	return {
+		fullBlisters: Math.floor(sealedPills / pillsPerBlister),
+		openBlisterPills: sealedPills % pillsPerBlister,
+		loosePills,
+	};
+}
+
+/**
+ * Convenience helper when medication object already contains stock fields.
+ */
+export function getBlisterStockFromMedication(med: Medication): BlisterStockSplit {
+	const total =
+		(med.packageType === "bottle"
+			? med.looseTablets + (med.stockAdjustment ?? 0)
+			: med.packCount * med.blistersPerPack * med.pillsPerBlister + med.looseTablets + (med.stockAdjustment ?? 0)) ?? 0;
+
+	return splitCurrentBlisterStock(total, med.pillsPerBlister, med.looseTablets);
+}