fix: resolve translation proxy shadowing name keys

The Proxy's get handler checked `prop in target` before looking up
translations. Since the target is a function, `Function.name` is a
built-in property that shadowed translation keys like `t.common.name`,
causing the raw proxy path to render instead of the translated string.

Move translation lookup before target property checks so i18n keys
always take priority. Also remove unnecessary `|| 'Name'` fallback
in CreateNotebookDialog.

frontend/src/components/notebooks/CreateNotebookDialog.tsx

@@ -75,7 +75,7 @@ export function CreateNotebookDialog({ open, onOpenChange }: CreateNotebookDialo
 
         <form onSubmit={handleSubmit(onSubmit)} className="space-y-4">
           <div className="space-y-2">
-            <Label htmlFor="notebook-name">{t.common.name || 'Name'} *</Label>
+            <Label htmlFor="notebook-name">{t.common.name} *</Label>
             <Input
               id="notebook-name"
               {...register('name')}

frontend/src/lib/hooks/use-translation.ts

@@ -78,12 +78,6 @@ export function useTranslation() {
             // eslint-disable-next-line @typescript-eslint/no-explicit-any
             return (target as any)[prop];
           }
-          
-          // Handle function's own properties
-          if (prop in target) {
-            // eslint-disable-next-line @typescript-eslint/no-explicit-any
-            return (target as any)[prop];
-          }
 
           if (typeof prop !== 'string') return undefined;
 
@@ -94,7 +88,9 @@ export function useTranslation() {
 
           const currentPath = path ? `${path}.${prop}` : prop;
 
-          // Try to get the translation
+          // Try to get the translation first (before checking target properties,
+          // since target is a function and has built-in properties like 'name'
+          // that would shadow translation keys)
           const result = i18nTranslateCopy(currentPath, { returnObjects: true });
 
           // If it's a leaf string, return it directly