fix: resizable plugins dialog

resources/web/dialog/PluginsDialog/styles.css

@@ -151,11 +151,13 @@ body {
   margin-right: auto;
 }
 
+/* Split pane: the list keeps --plugin-list-height of the dialog's content height (set by the
+   splitter drag, see InitPaneSplitter), the details pane takes what is left. Both panes shrink
+   before the layout overflows, so a short dialog degrades instead of clipping. */
 .content {
   min-height: 0;
-  display: grid;
-  grid-template-rows: minmax(220px, 1fr) 280px;
-  gap: 8px;
+  display: flex;
+  flex-direction: column;
 }
 
 .pane {
@@ -166,17 +168,60 @@ body {
   display: grid;
 }
 
+/* The pane minimums live in JS (SPLIT_MIN_LIST_PX / SPLIT_MIN_DETAILS_PX), which clamps the ratio
+   against the current height: as CSS min-heights they could not both be honored in a very short
+   dialog and the panes would overflow instead of shrinking. */
 .plugin-list-pane {
+  flex: 0 1 auto;
+  height: var(--plugin-list-height, 62%);
   grid-template-rows: auto minmax(0, 1fr);
 }
 
+/* basis 0, so the details pane takes the space the list leaves instead of letting its own content
+   height push back and shrink the list below --plugin-list-height. */
 .details-pane {
+  flex: 1 1 0;
   grid-template-rows: auto minmax(0, 1fr);
   padding: 12px;
   box-sizing: border-box;
   gap: 10px;
 }
 
+/* 9px of grab area for a 2px divider: the strip also supplies the gap between the panes. */
+.pane-splitter {
+  flex: 0 0 auto;
+  position: relative;
+  height: 9px;
+  cursor: ns-resize;
+  touch-action: none;
+}
+
+.pane-splitter::after {
+  content: "";
+  position: absolute;
+  top: 50%;
+  right: 0;
+  left: 0;
+  height: 2px;
+  transform: translateY(-50%);
+  border-radius: 1px;
+  background: transparent;
+  transition: background-color 0.12s ease;
+}
+
+.pane-splitter:hover::after {
+  background: var(--border-strong);
+}
+
+.pane-splitter.dragging::after {
+  background: var(--row-selected-outline);
+}
+
+/* Keep the resize cursor for the whole drag, wherever the pointer travels. */
+body.pane-resizing {
+  cursor: ns-resize;
+}
+
 .hdr {
   font-weight: 600;
   font-size: 12px;