Grant senior_editor oil editing, PDF export, and public recipe management

Add canManage computed (senior_editor + admin) to auth store and use it
for oil edit/delete buttons, PDF export, and public recipe section
visibility. Backend already allowed these operations for senior_editor.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

frontend/src/stores/auth.js

@@ -18,6 +18,9 @@ export const useAuthStore = defineStore('auth', () => {
   // Getters
   const isLoggedIn = computed(() => user.value.id !== null)
   const isAdmin = computed(() => user.value.role === 'admin')
+  const canManage = computed(() =>
+    ['senior_editor', 'admin'].includes(user.value.role)
+  )
   const canEdit = computed(() =>
     ['editor', 'senior_editor', 'admin'].includes(user.value.role)
   )
@@ -91,6 +94,7 @@ export const useAuthStore = defineStore('auth', () => {
     user,
     isLoggedIn,
     isAdmin,
+    canManage,
     canEdit,
     isBusiness,
     initToken,