Settings: fold Users and Organization into the Settings tabs

The left rail is back to the three places you actually go — Garage,
Charging, Settings — and user management moves inside Settings as an
admin-only tab, next to a new Organization tab that used to be a card
buried in the personal settings. Tab order is Personal settings, Users,
Organization, Integrations. /admin redirects to /settings?tab=users so
old links keep working, and ?tab= picks the starting tab in general.

AdminUsers moves from views/ to components/ since it is a panel now, not
a route, and its page header becomes a section header like its
neighbours. The personal panel was split in two around the integrations
markup, which left no gap between the Profile and Privacy cards; it is
one block again.

Creating a user gets an organization picker for superadmins, defaulting
to "no organization" so an org-less account stays a deliberate choice.
Admins see no picker: the server pins their members to their own org
regardless, which users_test.go now covers along with both superadmin
paths.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

Web App/web/src/i18n/pl.json

@@ -26,7 +26,6 @@
     "garage": "Garaż",
     "charging": "Ładowanie",
     "settings": "Ustawienia",
-    "users": "Użytkownicy",
     "lightMode": "Tryb jasny",
     "darkMode": "Tryb ciemny",
     "signedIn": "Zalogowano",
@@ -108,15 +107,15 @@
   },
 
   "admin": {
-    "eyebrow": "Administracja",
     "title": "Użytkownicy",
     "subtitleAll": "Konta ze wszystkich organizacji.",
     "subtitleOrg": "Konta w Twojej organizacji.",
-    "subtitleOrgsNote": "Organizacjami zarządza się w Ustawieniach.",
     "addUser": "Dodaj użytkownika",
     "colEmail": "E-mail",
     "colName": "Imię i nazwisko",
     "colOrganization": "Organizacja",
+    "noOrganization": "— Bez organizacji —",
+    "organizationHint": "Zostaw puste, aby utworzyć konto bez organizacji.",
     "colRole": "Rola",
     "colCreated": "Utworzono",
     "you": "(Ty)",
@@ -148,7 +147,9 @@
     "subtitle": "Zarządzaj kontem, wyglądem i danymi.",
     "tabs": {
       "personal": "Ustawienia osobiste",
-      "integrations": "Integracje"
+      "integrations": "Integracje",
+      "users": "Użytkownicy",
+      "organization": "Organizacja"
     },
 
     "account": {