fix(security): patch 3 vulnerabilities — IDOR, ownership bypass, XSS

V1: Add owner-scoped folder pagination (list_folders_by_owner_paginated)
  - New method in FolderRepository trait, PG implementation, service & handler
  - Prevents IDOR by filtering folder listings to authenticated user

V2: Enforce ownership checks on folder mutations
  - rename_folder, move_folder, delete_folder now require caller_id
  - Service verifies folder.owner_id == caller_id (returns 404 on mismatch)
  - Propagated to folder_handler, batch_handler, batch_operations, webdav_handler
  - delete_folder_with_trash upgraded from OptionalAuthUser to AuthUser
  - download_folder_zip now checks ownership before streaming

V3: Fix XSS in frontend via DOM APIs
  - sharedView.js: innerHTML → createElement + textContent
  - contextMenus.js: innerHTML → DOM construction for share dialog

Cleanup: removed unused OptionalAuthUser import, updated all stubs/mocks

static/locales/de.json

@@ -339,5 +339,13 @@
     "folder_deleted": "Ordner in Papierkorb verschoben",
     "item_deleted_permanently": "Element endgültig gelöscht",
     "trash_emptied": "Papierkorb erfolgreich geleert"
+  },
+  "batch": {
+    "one_selected": "1 Element ausgewählt",
+    "n_selected": "{{count}} Elemente ausgewählt",
+    "confirm_delete": "Möchten Sie wirklich {{count}} Elemente in den Papierkorb verschieben?",
+    "move_title": "{{count}} Element(e) verschieben",
+    "add_favorites": "Zu Favoriten hinzufügen",
+    "move_copy": "Verschieben oder kopieren"
   }
 }

static/locales/en.json

@@ -341,5 +341,13 @@
     "trash_emptied": "Trash emptied successfully",
     "title": "Notifications",
     "empty": "No notifications"
+  },
+  "batch": {
+    "one_selected": "1 item selected",
+    "n_selected": "{{count}} items selected",
+    "confirm_delete": "Are you sure you want to move {{count}} items to trash?",
+    "move_title": "Move {{count}} item(s)",
+    "add_favorites": "Add to favorites",
+    "move_copy": "Move or copy"
   }
 }

static/locales/es.json

@@ -341,5 +341,13 @@
     "trash_emptied": "Papelera vaciada correctamente",
     "title": "Notificaciones",
     "empty": "Sin notificaciones"
+  },
+  "batch": {
+    "one_selected": "1 elemento seleccionado",
+    "n_selected": "{{count}} elementos seleccionados",
+    "confirm_delete": "¿Estás seguro de que quieres mover {{count}} elementos a la papelera?",
+    "move_title": "Mover {{count}} elemento(s)",
+    "add_favorites": "Añadir a favoritos",
+    "move_copy": "Mover o copiar"
   }
 }

static/locales/fa.json

@@ -314,5 +314,13 @@
     "accessed": "دسترسی یافته",
     "empty_state": "هنوز هیچ پروندهٔ اخیر وجود ندارد",
     "empty_hint": "پرونده‌هایی که باز می‌کنید اینجا ظاهر می‌شوند"
+  },
+  "batch": {
+    "one_selected": "۱ مورد انتخاب شده",
+    "n_selected": "{{count}} مورد انتخاب شده",
+    "confirm_delete": "آیا مطمئنید که می‌خواهید {{count}} مورد را به سطل زباله منتقل کنید؟",
+    "move_title": "انتقال {{count}} مورد",
+    "add_favorites": "افزودن به موارد علاقه‌مند",
+    "move_copy": "انتقال یا کپی"
   }
 }

static/locales/fr.json

@@ -339,5 +339,13 @@
     "folder_deleted": "Dossier déplacé vers la corbeille",
     "item_deleted_permanently": "Élément supprimé définitivement",
     "trash_emptied": "Corbeille vidée avec succès"
+  },
+  "batch": {
+    "one_selected": "1 élément sélectionné",
+    "n_selected": "{{count}} éléments sélectionnés",
+    "confirm_delete": "Voulez-vous vraiment déplacer {{count}} éléments vers la corbeille ?",
+    "move_title": "Déplacer {{count}} élément(s)",
+    "add_favorites": "Ajouter aux favoris",
+    "move_copy": "Déplacer ou copier"
   }
 }

static/locales/it.json

@@ -313,7 +313,7 @@
  "fa": "Persiano",
  "fr": "Francese",
  "de": "Tedesco",
- "pt": "Portoghese"
+ "pt": "Portoghese",
  "it": "Italiano"
  }
  },
@@ -340,5 +340,13 @@
  "folder_deleted": "Cartella spostata nel cestino",
  "item_deleted_permanently": "Elemento eliminato definitivamente",
  "trash_emptied": "Cestino svuotato con successo"
+ },
+ "batch": {
+  "one_selected": "1 elemento selezionato",
+  "n_selected": "{{count}} elementi selezionati",
+  "confirm_delete": "Sei sicuro di voler spostare {{count}} elementi nel cestino?",
+  "move_title": "Sposta {{count}} elemento/i",
+  "add_favorites": "Aggiungi ai preferiti",
+  "move_copy": "Sposta o copia"
  }
 }

static/locales/pt.json

@@ -339,5 +339,13 @@
     "folder_deleted": "Pasta movida para a lixeira",
     "item_deleted_permanently": "Item excluído permanentemente",
     "trash_emptied": "Lixeira esvaziada com sucesso"
+  },
+  "batch": {
+    "one_selected": "1 item selecionado",
+    "n_selected": "{{count}} itens selecionados",
+    "confirm_delete": "Tem certeza de que deseja mover {{count}} itens para a lixeira?",
+    "move_title": "Mover {{count}} item(ns)",
+    "add_favorites": "Adicionar aos favoritos",
+    "move_copy": "Mover ou copiar"
   }
 }

static/locales/zh.json

@@ -276,5 +276,13 @@
     "accessed": "访问于",
     "empty_state": "没有最近文件",
     "empty_hint": "您打开的文件将显示在这里"
+  },
+  "batch": {
+    "one_selected": "已选择 1 个项目",
+    "n_selected": "已选择 {{count}} 个项目",
+    "confirm_delete": "确定要将 {{count}} 个项目移至回收站吗？",
+    "move_title": "移动 {{count}} 个项目",
+    "add_favorites": "添加到收藏夹",
+    "move_copy": "移动或复制"
   }
 }