mobile: add explicit close button to nav drawer

apps/web/src/components/ProjectSidebar.tsx

@@ -1,6 +1,6 @@
 import { useEffect, useMemo, useRef, useState } from 'react';
 import { NavLink, useLocation, useNavigate } from 'react-router-dom';
-import { ChevronRight, ExternalLink, Folder, MessageSquare, Plus, Settings as SettingsIcon } from 'lucide-react';
+import { ChevronRight, ExternalLink, Folder, MessageSquare, Plus, Settings as SettingsIcon, X } from 'lucide-react';
 import { toast } from 'sonner';
 import { Button } from '@/components/ui/button';
 import { sessionEvents } from '@/hooks/sessionEvents';
@@ -221,9 +221,21 @@ export function ProjectSidebar() {
         <NavLink to="/" className="font-semibold tracking-tight text-base">
           BooCode
         </NavLink>
-        <Button size="icon-sm" variant="ghost" onClick={() => setAddOpen(true)} aria-label="Add project">
-          <Plus />
-        </Button>
+        <div className="flex items-center gap-1">
+          <Button size="icon-sm" variant="ghost" onClick={() => setAddOpen(true)} aria-label="Add project">
+            <Plus />
+          </Button>
+          {isMobile && (
+            <Button
+              size="icon-sm"
+              variant="ghost"
+              onClick={() => setDrawerOpen(false)}
+              aria-label="Close sidebar"
+            >
+              <X />
+            </Button>
+          )}
+        </div>
       </div>
 
       {isMobile && (pull.pullDist > 0 || pull.refreshing) && (