feat: Adressbuch mit Kundennummer, Update-Flow und interne Einträge

- Menüpunkt "Kunden" in "Adressbuch" umbenannt und App-Label
  "Verfügbare Jobs" zu "Auftragsliste" geändert (alle 10 Sprachen)
- Fortlaufende Kundennummer (usrId) ab 10000 über neuen
  SequenceGeneratorService und Counter-Dokument in misc-Collection
- Abholung/Lieferstation-Dialog: Änderungen an verknüpften
  Stammdaten aktualisieren den bestehenden Adressbuch-Eintrag
  statt einen neuen zu erzeugen; Checkbox-Label wechselt zu
  "Adresse im Adressbuch aktualisieren"
- Geänderte Adressen ohne Checkbox werden als interner Customer
  (internal=true) gesichert und im Adressbuch ausgeblendet
- E-Mail in AddCustomer und in Stations-Dialogen kein Pflichtfeld
  mehr; "(Login)" aus profile.email entfernt
- Manuelles Beenden eines Auftrags öffnet neue Seite
  JobManualCompleteView statt eines Dialogs

backend/src/main/resources/messages_en.properties

@@ -5,7 +5,7 @@ dialog.confirm=Confirm
 # Navigation and Main Layout
 nav.jobs=Jobs
 nav.job.create=Create Job
-nav.customers=Customers
+nav.customers=Address Book
 nav.appusers=App Users
 nav.statistics=Statistics
 nav.invoices=Invoices
@@ -31,7 +31,7 @@ profile.lastname=Last Name
 profile.phone=Phone Number
 profile.fax=Phone (Fax)
 profile.mobile=Phone (Mobile)
-profile.email=Email Address (Login)*
+profile.email=Email Address
 profile.street=Street
 profile.housenr=House No.
 profile.addressadd=Address Suffix
@@ -447,7 +447,8 @@ addjob.address.city.placeholder.pickup=City (Pickup)
 addjob.address.city.placeholder.delivery=City (Delivery)
 addjob.address.delivery.street.placeholder=Street (Delivery)
 addjob.address.delivery.addition.placeholder=Address suffix (Delivery)
-addjob.address.save=Save Address
+addjob.address.save=Add address to address book
+addjob.address.update=Update address in address book
 addjob.section.pickup=Pickup
 addjob.section.delivery=Delivery
 addjob.stations.apply=Apply Stations
@@ -513,7 +514,8 @@ addjob.tasks.photo.min=Min. Photos
 addjob.tasks.photo.max=Max. Photos
 addjob.tasks.barcode.min=Min. Barcodes
 addjob.tasks.barcode.max=Max. Barcodes
-addjob.tasks.signature.noconfig=No configuration required
+addjob.tasks.signature.notelabel=Note (optional)
+addjob.tasks.signature.notelabel.placeholder=Enter hint text for the note
 addjob.tasks.todolist.title=To-Do List
 addjob.tasks.todolist.item.placeholder=Enter to-do
 addjob.tasks.todolist.add=Add To-Do