fix: stabilize dashboard modal and image click behavior (#267)

* feat: make medication names clickable in Dashboard dose schedule

Add click handlers to med-name-stack divs in all three dose schedule
sections (past, current/overdue, future) on DashboardPage, opening the
MedDetail modal on click.

Add early-return guards to all four modal openers in AppContext
(openMedDetail, openImageLightbox, openScheduleLightbox, openUserFilter)
to prevent duplicate pushState entries on double-click, which caused
unexpected navigation to the Medications page.

Closes #266

* fix: stabilize dashboard modal and image click handling

* fix: close medication detail on first backdrop click

frontend/src/components/MedDetailModal.tsx

@@ -648,8 +648,11 @@ export function MedDetailModal({
 			className="modal-overlay med-detail-overlay"
 			onClick={onClose}
 			onKeyDown={(e) => {
-				if (showEditStockModal) return;
-				if (e.key === "Escape") onClose();
+				if (showEditStockModal || showImageLightbox || showRefillModal) return;
+				if (e.key === "Escape") {
+					e.stopPropagation();
+					onClose();
+				}
 			}}
 		>
 			<div