fix: add isSaving prop and back-to-dashboard navigation to Toolbar

Add isSaving as a prop so the save button properly shows disabled/spinner
state. Add a back arrow link to /dashboard for editor navigation.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/components/editor/Toolbar.tsx

@@ -1,5 +1,6 @@
 'use client'
 
+import Link from 'next/link'
 import type { ConnectionState, PresenceUser } from '@/lib/collaboration/realtime'
 import PresenceAvatars from './PresenceAvatars'
 
@@ -8,6 +9,7 @@ type ToolbarProps = {
   onAddChoice: () => void
   onAddVariable: () => void
   onSave: () => void
+  isSaving?: boolean
   onExport: () => void
   onExportRenpy: () => void
   onImport: () => void
@@ -36,6 +38,7 @@ export default function Toolbar({
   onAddChoice,
   onAddVariable,
   onSave,
+  isSaving,
   onExport,
   onExportRenpy,
   onImport,
@@ -47,6 +50,15 @@ export default function Toolbar({
   return (
     <div className="flex items-center justify-between border-b border-zinc-200 bg-zinc-50 px-4 py-2 dark:border-zinc-700 dark:bg-zinc-800">
       <div className="flex items-center gap-2">
+        <Link
+          href="/dashboard"
+          className="mr-2 flex items-center gap-1 text-zinc-600 hover:text-zinc-900 dark:text-zinc-400 dark:hover:text-zinc-50"
+          title="Back to Dashboard"
+        >
+          <svg xmlns="http://www.w3.org/2000/svg" className="h-5 w-5" viewBox="0 0 20 20" fill="currentColor">
+            <path fillRule="evenodd" d="M9.707 16.707a1 1 0 01-1.414 0l-6-6a1 1 0 010-1.414l6-6a1 1 0 011.414 1.414L5.414 9H17a1 1 0 110 2H5.414l4.293 4.293a1 1 0 010 1.414z" clipRule="evenodd" />
+          </svg>
+        </Link>
         <span className="mr-2 text-sm font-medium text-zinc-500 dark:text-zinc-400">
           Add Node:
         </span>