Add dropdown with toggle functionality to OwnerPicker

Introduced a dropdown feature to the OwnerPicker component, allowing users to search or browse owners more effectively. The dropdown can be toggled open/closed and includes improved styling for better user experience. Added click-outside functionality to automatically close the dropdown when users interact elsewhere.

frontend/src/styles.css

@@ -752,6 +752,7 @@ button {
 .owner-picker {
   display: grid;
   gap: 8px;
+  position: relative;
 }
 
 .owner-selected {
@@ -774,14 +775,48 @@ button {
   font-weight: 600;
 }
 
+.owner-search-shell {
+  display: grid;
+  grid-template-columns: 1fr auto;
+  gap: 0;
+}
+
+.owner-search-shell.open .owner-search-input {
+  border-bottom-left-radius: 0;
+  border-bottom-right-radius: 0;
+}
+
 .owner-search-input {
   width: 100%;
+  border-top-right-radius: 0;
+  border-bottom-right-radius: 0;
+}
+
+.owner-search-toggle {
+  border-top-left-radius: 0;
+  border-bottom-left-radius: 0;
+  min-width: 38px;
+  font-weight: 700;
+  padding: 0 10px;
+}
+
+.owner-dropdown {
+  position: absolute;
+  left: 0;
+  right: 0;
+  top: calc(100% - 2px);
+  z-index: 10;
+  border: 1px solid #3c73ac;
+  border-radius: 0 0 10px 10px;
+  background: #0f2549;
+  box-shadow: 0 12px 26px #03112777;
+  padding: 8px;
 }
 
 .owner-search-results {
   display: grid;
   gap: 6px;
-  max-height: 150px;
+  max-height: 180px;
   overflow: auto;
   padding-right: 2px;
 }