Event editing dialog and many other event-related improvements.

layout.css

@@ -131,13 +131,14 @@ header {
 
 /* Overlay sitting above the day cells, same 7-col grid */
 .week-row > .days-grid > .week-overlay {
-  margin-top: 1.2em;
+  margin-top: 1.5em;
   position: absolute;
   inset: 0;
   pointer-events: none;
   display: grid;
   grid-template-columns: repeat(7, 1fr);
   grid-auto-rows: 1fr;
+  row-gap: 0; /* eliminate gaps so space is fully usable */
   z-index: 15;
 }