feat: add address book directories with drag-and-drop and editor picker

- Show address books in sidebar organized by personal directories and
  shared accounts, replacing the flat shared accounts list
- Make contact list items draggable with multi-select support using
  native HTML5 drag-and-drop (application/x-contact-ids MIME type)
- Add drop targets on sidebar address book items with visual feedback
- Add moveContactToAddressBook store method supporting same-account
  updates and cross-account create+delete moves
- Add address book picker dropdown in contact create/edit form
- Update ContactCategory type from sharedAccountId to addressBookId
- Add address_books translations to all 8 locales
- Fix contact-list-item tests for new selectedContactIds prop

locales/de/common.json

@@ -1469,6 +1469,16 @@
       "all": "Alle",
       "groups": "Gruppen"
     },
+    "shared": {
+      "title": "Geteilt"
+    },
+    "address_books": {
+      "title": "Verzeichnisse",
+      "moved": "Kontakt verschoben nach {name}",
+      "moved_plural": "{count} Kontakte verschoben nach {name}",
+      "move_failed": "Kontakt konnte nicht verschoben werden",
+      "address_book": "Verzeichnis"
+    },
     "detail": {
       "emails": "E-Mail-Adressen",
       "phones": "Telefonnummern",
@@ -1524,6 +1534,8 @@
     "form": {
       "create_title": "Neuer Kontakt",
       "edit_title": "Kontakt bearbeiten",
+      "section_address_book": "Verzeichnis",
+      "select_address_book": "Verzeichnis auswählen...",
       "section_identity": "Name & Identität",
       "section_work": "Beruf & Organisation",
       "prefix": "Anrede",

locales/en/common.json

@@ -1469,6 +1469,16 @@
       "all": "All",
       "groups": "Groups"
     },
+    "shared": {
+      "title": "Shared"
+    },
+    "address_books": {
+      "title": "Directories",
+      "moved": "Contact moved to {name}",
+      "moved_plural": "{count} contacts moved to {name}",
+      "move_failed": "Failed to move contact",
+      "address_book": "Directory"
+    },
     "detail": {
       "emails": "Email Addresses",
       "phones": "Phone Numbers",
@@ -1524,6 +1534,8 @@
     "form": {
       "create_title": "New Contact",
       "edit_title": "Edit Contact",
+      "section_address_book": "Directory",
+      "select_address_book": "Select a directory...",
       "section_identity": "Name & Identity",
       "section_work": "Work & Organization",
       "prefix": "Prefix",

locales/es/common.json

@@ -1469,6 +1469,16 @@
       "all": "Todos",
       "groups": "Grupos"
     },
+    "shared": {
+      "title": "Compartidos"
+    },
+    "address_books": {
+      "title": "Directorios",
+      "moved": "Contacto movido a {name}",
+      "moved_plural": "{count} contactos movidos a {name}",
+      "move_failed": "Error al mover el contacto",
+      "address_book": "Directorio"
+    },
     "detail": {
       "emails": "Direcciones de correo",
       "phones": "Números de teléfono",
@@ -1524,6 +1534,8 @@
     "form": {
       "create_title": "Nuevo contacto",
       "edit_title": "Editar contacto",
+      "section_address_book": "Directorio",
+      "select_address_book": "Seleccionar un directorio...",
       "section_identity": "Nombre e identidad",
       "section_work": "Trabajo y organización",
       "prefix": "Prefijo",

locales/fr/common.json

@@ -1469,6 +1469,16 @@
       "all": "Tous",
       "groups": "Groupes"
     },
+    "shared": {
+      "title": "Partagés"
+    },
+    "address_books": {
+      "title": "Répertoires",
+      "moved": "Contact déplacé vers {name}",
+      "moved_plural": "{count} contacts déplacés vers {name}",
+      "move_failed": "Échec du déplacement du contact",
+      "address_book": "Répertoire"
+    },
     "detail": {
       "emails": "Adresses e-mail",
       "phones": "Numéros de téléphone",
@@ -1524,6 +1534,8 @@
     "form": {
       "create_title": "Nouveau contact",
       "edit_title": "Modifier le contact",
+      "section_address_book": "Répertoire",
+      "select_address_book": "Sélectionner un répertoire...",
       "section_identity": "Nom et identité",
       "section_work": "Travail et organisation",
       "prefix": "Préfixe",

locales/it/common.json

@@ -1469,6 +1469,16 @@
       "all": "Tutti",
       "groups": "Gruppi"
     },
+    "shared": {
+      "title": "Condivisi"
+    },
+    "address_books": {
+      "title": "Rubriche",
+      "moved": "Contatto spostato in {name}",
+      "moved_plural": "{count} contatti spostati in {name}",
+      "move_failed": "Impossibile spostare il contatto",
+      "address_book": "Rubrica"
+    },
     "detail": {
       "emails": "Indirizzi email",
       "phones": "Numeri di telefono",
@@ -1524,6 +1534,8 @@
     "form": {
       "create_title": "Nuovo contatto",
       "edit_title": "Modifica contatto",
+      "section_address_book": "Rubrica",
+      "select_address_book": "Seleziona una rubrica...",
       "section_identity": "Nome e identità",
       "section_work": "Lavoro e organizzazione",
       "prefix": "Prefisso",

locales/ja/common.json

@@ -1469,6 +1469,16 @@
       "all": "すべて",
       "groups": "グループ"
     },
+    "shared": {
+      "title": "共有"
+    },
+    "address_books": {
+      "title": "ディレクトリ",
+      "moved": "連絡先を {name} に移動しました",
+      "moved_plural": "{count} 件の連絡先を {name} に移動しました",
+      "move_failed": "連絡先の移動に失敗しました",
+      "address_book": "ディレクトリ"
+    },
     "detail": {
       "emails": "メールアドレス",
       "phones": "電話番号",
@@ -1524,6 +1534,8 @@
     "form": {
       "create_title": "新しい連絡先",
       "edit_title": "連絡先を編集",
+      "section_address_book": "ディレクトリ",
+      "select_address_book": "ディレクトリを選択...",
       "section_identity": "名前と識別情報",
       "section_work": "職業と組織",
       "prefix": "敬称",

locales/nl/common.json

@@ -1469,6 +1469,16 @@
       "all": "Alle",
       "groups": "Groepen"
     },
+    "shared": {
+      "title": "Gedeeld"
+    },
+    "address_books": {
+      "title": "Adresboeken",
+      "moved": "Contact verplaatst naar {name}",
+      "moved_plural": "{count} contacten verplaatst naar {name}",
+      "move_failed": "Verplaatsen van contact mislukt",
+      "address_book": "Adresboek"
+    },
     "detail": {
       "emails": "E-mailadressen",
       "phones": "Telefoonnummers",
@@ -1524,6 +1534,8 @@
     "form": {
       "create_title": "Nieuw contact",
       "edit_title": "Contact bewerken",
+      "section_address_book": "Adresboek",
+      "select_address_book": "Selecteer een adresboek...",
       "section_identity": "Naam en identiteit",
       "section_work": "Werk en organisatie",
       "prefix": "Voorvoegsel",

locales/pt/common.json

@@ -1469,6 +1469,16 @@
       "all": "Todos",
       "groups": "Grupos"
     },
+    "shared": {
+      "title": "Compartilhados"
+    },
+    "address_books": {
+      "title": "Diretórios",
+      "moved": "Contato movido para {name}",
+      "moved_plural": "{count} contatos movidos para {name}",
+      "move_failed": "Falha ao mover o contato",
+      "address_book": "Diretório"
+    },
     "detail": {
       "emails": "Endereços de e-mail",
       "phones": "Números de telefone",
@@ -1524,6 +1534,8 @@
     "form": {
       "create_title": "Novo contato",
       "edit_title": "Editar contato",
+      "section_address_book": "Diretório",
+      "select_address_book": "Selecionar um diretório...",
       "section_identity": "Nome e identidade",
       "section_work": "Trabalho e organização",
       "prefix": "Prefixo",