ui: persist issue properties pane visibility in localStorage

Store the open/closed state of the properties panel in localStorage
so it persists across navigations, issues, and companies.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

ui/src/components/PropertiesPanel.tsx

@@ -4,15 +4,15 @@ import { Button } from "@/components/ui/button";
 import { ScrollArea } from "@/components/ui/scroll-area";
 
 export function PropertiesPanel() {
-  const { panelContent, closePanel } = usePanel();
+  const { panelContent, panelVisible, setPanelVisible } = usePanel();
 
-  if (!panelContent) return null;
+  if (!panelContent || !panelVisible) return null;
 
   return (
     <aside className="hidden md:flex w-80 border-l border-border bg-card flex-col shrink-0">
       <div className="flex items-center justify-between px-4 py-2 border-b border-border">
         <span className="text-sm font-medium">Properties</span>
-        <Button variant="ghost" size="icon-xs" onClick={closePanel}>
+        <Button variant="ghost" size="icon-xs" onClick={() => setPanelVisible(false)}>
           <X className="h-4 w-4" />
         </Button>
       </div>