fix(electrobun): XDG dirs, sanitized errors, themed dropdowns + checkboxes

- PathBrowser: dynamic XDG shortcuts (only shows dirs that exist)
- Errors sanitized: "Directory not found" instead of raw ENOENT
- Select dropdowns: custom arrow, themed options, appearance:none
- Checkboxes: custom styled with --ctp-blue check, themed border

ui-electrobun/src/mainview/PathBrowser.svelte

@@ -10,12 +10,34 @@
   let { onSelect, onClose }: Props = $props();
 
   let HOME = $state('/home');
-  const SHORTCUTS = [
+  let shortcuts = $state([
     { label: 'Home', path: '~' },
-    { label: 'Desktop', path: '~/Desktop' },
-    { label: 'Documents', path: '~/Documents' },
     { label: '/tmp', path: '/tmp' },
-  ];
+  ]);
+
+  // Load XDG user directories from backend
+  async function loadXdgDirs() {
+    try {
+      const r = await appRpc.request['files.homeDir']({});
+      if (r?.path) HOME = r.path;
+      // Check which XDG dirs actually exist
+      const candidates = [
+        { label: 'Desktop', env: 'XDG_DESKTOP_DIR', fallback: `${HOME}/Desktop` },
+        { label: 'Documents', env: 'XDG_DOCUMENTS_DIR', fallback: `${HOME}/Documents` },
+        { label: 'Downloads', env: 'XDG_DOWNLOAD_DIR', fallback: `${HOME}/Downloads` },
+        { label: 'Projects', env: 'XDG_PROJECTS_DIR', fallback: `${HOME}/Projects` },
+      ];
+      // Validate each via files.browse (only add if dir exists)
+      const existing: typeof shortcuts = [{ label: 'Home', path: '~' }];
+      for (const c of candidates) {
+        const path = c.fallback.replace(HOME, '~');
+        const res = await appRpc.request['files.browse']({ path: c.fallback }).catch(() => null);
+        if (res && !res.error) existing.push({ label: c.label, path });
+      }
+      existing.push({ label: '/tmp', path: '/tmp' });
+      shortcuts = existing;
+    } catch {}
+  }
 
   let currentPath = $state('~');
   let entries = $state<Array<{ name: string; type: 'file' | 'dir'; size: number }>>([]);
@@ -65,7 +87,15 @@
       }
       currentPath = dirPath;
     } catch (err) {
-      error = err instanceof Error ? err.message : String(err);
+      const raw = err instanceof Error ? err.message : String(err);
+      // Sanitize: show user-friendly message, not raw ENOENT
+      if (raw.includes('ENOENT') || raw.includes('no such file')) {
+        error = 'Directory not found';
+      } else if (raw.includes('EACCES') || raw.includes('permission')) {
+        error = 'Permission denied';
+      } else {
+        error = 'Cannot access this directory';
+      }
       entries = [];
     } finally {
       loading = false;
@@ -89,6 +119,7 @@
 
   // Load initial directory
   $effect(() => {
+    loadXdgDirs();
     loadDir('~');
   });
 </script>
@@ -102,7 +133,7 @@
 
   <!-- Shortcuts -->
   <div class="pb-shortcuts">
-    {#each SHORTCUTS as sc}
+    {#each shortcuts as sc}
       <button class="pb-shortcut" onclick={() => navigateTo(sc.path)}>{sc.label}</button>
     {/each}
   </div>