feat: add ScriptManagePage with routing and 'Manage Templates' link

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

frontend/src/pages/ScriptManagePage.tsx

@@ -0,0 +1,42 @@
+import { useState } from 'react'
+import { ScriptTemplateListView } from '@/components/script-editor/ScriptTemplateListView'
+import { ScriptTemplateEditor } from '@/components/script-editor/ScriptTemplateEditor'
+
+export default function ScriptManagePage() {
+  const [mode, setMode] = useState<'list' | 'edit'>('list')
+  const [editingId, setEditingId] = useState<string | null>(null)
+
+  const handleEdit = (id: string) => {
+    setEditingId(id)
+    setMode('edit')
+  }
+
+  const handleCreate = () => {
+    setEditingId(null)
+    setMode('edit')
+  }
+
+  const handleBack = () => {
+    setEditingId(null)
+    setMode('list')
+  }
+
+  const handleSaved = () => {
+    setEditingId(null)
+    setMode('list')
+  }
+
+  return (
+    <div className="p-6 max-w-5xl mx-auto">
+      {mode === 'list' ? (
+        <ScriptTemplateListView onEdit={handleEdit} onCreate={handleCreate} />
+      ) : (
+        <ScriptTemplateEditor
+          templateId={editingId}
+          onBack={handleBack}
+          onSaved={handleSaved}
+        />
+      )}
+    </div>
+  )
+}