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/styles.css

@@ -2212,6 +2212,9 @@ button.has-validation-error {
 .time-main .med-name span.clickable {
 	cursor: pointer;
 }
+.time-main .med-name .med-name-stack.clickable {
+	cursor: pointer;
+}
 .time-main .med-name span.clickable:hover .med-avatar {
 	transform: scale(1.1);
 	box-shadow: 0 4px 12px rgba(0, 0, 0, 0.2);