fix: correct stock calculation for both manual and automatic modes (#136)

Manual mode: Use takenAt timestamp instead of dose date-only comparison
to correctly distinguish doses taken before vs after stock correction
on the same day. Add polling race condition guard (mutationInFlightRef)
so Take/Undo immediately reflects in dashboard stock.

Automatic mode: Grid-align effectiveStart to the medication schedule
and use hybrid consumed calculation (time-based + early-taken doses)
for accurate stock counting.

frontend/src/hooks/useDoses.ts

@@ -2,11 +2,12 @@
 // useDoses Hook - Dose tracking state and operations
 // =============================================================================
 
-import { useCallback, useEffect, useState } from "react";
+import { useCallback, useEffect, useRef, useState } from "react";
 
 export interface UseDosesReturn {
 	takenDoses: Set<string>;
 	setTakenDoses: React.Dispatch<React.SetStateAction<Set<string>>>;
+	takenDoseTimestamps: Map<string, number>;
 	dismissedDoses: Set<string>;
 	showClearMissedConfirm: boolean;
 	setShowClearMissedConfirm: (show: boolean) => void;
@@ -19,25 +20,39 @@ export interface UseDosesReturn {
 
 export function useDoses(): UseDosesReturn {
 	const [takenDoses, setTakenDoses] = useState<Set<string>>(new Set());
+	const [takenDoseTimestamps, setTakenDoseTimestamps] = useState<Map<string, number>>(new Map());
 	const [dismissedDoses, setDismissedDoses] = useState<Set<string>>(new Set());
 	const [showClearMissedConfirm, setShowClearMissedConfirm] = useState(false);
 
+	// Track in-flight mutations to prevent polling from overwriting optimistic updates
+	const mutationInFlightRef = useRef(0);
+
 	// Load taken doses from server
 	const loadTakenDoses = useCallback(async () => {
+		// Skip polling while mutations are in-flight to prevent race conditions
+		// where a poll response with stale data overwrites optimistic updates
+		if (mutationInFlightRef.current > 0) return;
+
 		try {
 			const res = await fetch("/api/doses/taken", { credentials: "include" });
 			if (res.ok) {
+				// Double-check no mutation started while we were fetching
+				if (mutationInFlightRef.current > 0) return;
+
 				const data = await res.json();
 				const taken = new Set<string>();
+				const timestamps = new Map<string, number>();
 				const dismissed = new Set<string>();
 				for (const d of data.doses) {
 					if (d.dismissed) {
 						dismissed.add(d.doseId);
 					} else {
 						taken.add(d.doseId);
+						timestamps.set(d.doseId, d.takenAt);
 					}
 				}
 				setTakenDoses(taken);
+				setTakenDoseTimestamps(timestamps);
 				setDismissedDoses(dismissed);
 			}
 			// Don't reset on error - keep current state
@@ -77,59 +92,91 @@ export function useDoses(): UseDosesReturn {
 		[takenDoses, getDoseId]
 	);
 
-	const markDoseTaken = useCallback(async (doseId: string) => {
-		// Optimistic update
-		setTakenDoses((prev) => {
-			const next = new Set(prev);
-			next.add(doseId);
-			return next;
-		});
-
-		// Send to server
-		try {
-			await fetch("/api/doses/taken", {
-				method: "POST",
-				headers: { "Content-Type": "application/json" },
-				credentials: "include",
-				body: JSON.stringify({ doseId }),
-			});
-		} catch {
-			// Revert on error
-			setTakenDoses((prev) => {
-				const next = new Set(prev);
-				next.delete(doseId);
-				return next;
-			});
-		}
-	}, []);
-
-	const undoDoseTaken = useCallback(async (doseId: string) => {
-		// Optimistic update
-		setTakenDoses((prev) => {
-			const next = new Set(prev);
-			next.delete(doseId);
-			return next;
-		});
-
-		// Send to server
-		try {
-			await fetch(`/api/doses/taken/${encodeURIComponent(doseId)}`, {
-				method: "DELETE",
-				credentials: "include",
-			});
-		} catch {
-			// Revert on error
+	const markDoseTaken = useCallback(
+		async (doseId: string) => {
+			// Optimistic update
+			mutationInFlightRef.current++;
 			setTakenDoses((prev) => {
 				const next = new Set(prev);
 				next.add(doseId);
 				return next;
 			});
-		}
-	}, []);
+			setTakenDoseTimestamps((prev) => {
+				const next = new Map(prev);
+				next.set(doseId, Date.now());
+				return next;
+			});
+
+			// Send to server
+			try {
+				await fetch("/api/doses/taken", {
+					method: "POST",
+					headers: { "Content-Type": "application/json" },
+					credentials: "include",
+					body: JSON.stringify({ doseId }),
+				});
+			} catch {
+				// Revert on error
+				setTakenDoses((prev) => {
+					const next = new Set(prev);
+					next.delete(doseId);
+					return next;
+				});
+				setTakenDoseTimestamps((prev) => {
+					const next = new Map(prev);
+					next.delete(doseId);
+					return next;
+				});
+			} finally {
+				mutationInFlightRef.current--;
+				// Re-sync with server after mutation completes
+				loadTakenDoses();
+			}
+		},
+		[loadTakenDoses]
+	);
+
+	const undoDoseTaken = useCallback(
+		async (doseId: string) => {
+			// Optimistic update
+			mutationInFlightRef.current++;
+			setTakenDoses((prev) => {
+				const next = new Set(prev);
+				next.delete(doseId);
+				return next;
+			});
+			setTakenDoseTimestamps((prev) => {
+				const next = new Map(prev);
+				next.delete(doseId);
+				return next;
+			});
+
+			// Send to server
+			try {
+				await fetch(`/api/doses/taken/${encodeURIComponent(doseId)}`, {
+					method: "DELETE",
+					credentials: "include",
+				});
+			} catch {
+				// Revert on error
+				setTakenDoses((prev) => {
+					const next = new Set(prev);
+					next.add(doseId);
+					return next;
+				});
+			} finally {
+				mutationInFlightRef.current--;
+				// Re-sync with server after mutation completes
+				loadTakenDoses();
+			}
+		},
+		[loadTakenDoses]
+	);
 
 	return {
 		takenDoses,
 		setTakenDoses,
+		takenDoseTimestamps,
 		dismissedDoses,
 		showClearMissedConfirm,
 		setShowClearMissedConfirm,