refactor(studio): rename 笔记本 to 空间 in workspace nav and notebook pages

统一术语:侧边栏「新建笔记本/所有笔记本」、笔记列表与笔记本管理页的
新建按钮与弹窗标题，全部由"笔记本"改为"空间"。

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

frontend-web/src/pages/LightAppNoteListPage.tsx

@@ -122,7 +122,7 @@ export default function LightAppNoteListPage() {
           >
             <Plus className="h-5 w-5" />
           </span>
-          <span className="text-base font-medium">新建笔记本</span>
+          <span className="text-base font-medium">新建空间</span>
         </button>
       );
     }
@@ -146,7 +146,7 @@ export default function LightAppNoteListPage() {
         >
           <Plus className="h-5 w-5" />
         </span>
-        <span className="text-base font-medium">新建笔记本</span>
+        <span className="text-base font-medium">新建空间</span>
       </button>
     );
   };

frontend-web/src/pages/StudioNotebooksPage.tsx

@@ -186,7 +186,7 @@ export default function StudioNotebooksPage() {
           className="flex items-center gap-1.5 rounded-full bg-primary px-5 py-2.5 text-sm font-medium text-primary-foreground transition-colors hover:bg-primary/90"
         >
           <Plus className="size-4" />
-          新建笔记本
+          新建空间
         </button>
       </div>
 
@@ -199,20 +199,20 @@ export default function StudioNotebooksPage() {
         {isLoading
           ? Array.from({ length: 8 }).map((_, i) => <NotebookCardSkeleton key={i} />)
           : notebooks.map((nb) => (
-              <NotebookCard
-                key={nb.id}
-                nb={nb}
-                onRename={(nb) => { setRenameTarget(nb); setRenameName(nb.name); setRenameError(""); }}
-                onDelete={(nb) => { setDeleteTarget(nb); setDeleteError(""); }}
-              />
-            ))}
+            <NotebookCard
+              key={nb.id}
+              nb={nb}
+              onRename={(nb) => { setRenameTarget(nb); setRenameName(nb.name); setRenameError(""); }}
+              onDelete={(nb) => { setDeleteTarget(nb); setDeleteError(""); }}
+            />
+          ))}
       </div>
 
       {/* ── 新建 Dialog ── */}
       <Dialog open={createOpen} onOpenChange={(v) => !creating && setCreateOpen(v)}>
         <DialogContent className="sm:max-w-md">
           <DialogHeader>
-            <DialogTitle>新建笔记本</DialogTitle>
+            <DialogTitle>新建空间</DialogTitle>
           </DialogHeader>
           <div className="flex flex-col gap-4 pt-2">
             <input