docs: LT Wahl/Teamer admin + Verantwortlichen self-registration screens

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

client/app/README.md

@@ -44,9 +44,17 @@ Teamer login only).
   access token refreshed on restart. `GET /auth/me` resolves the role.
 - **Home** (`lib/screens/home_screen.dart`) — identity card + navigation.
 - **Verwaltung** (`lib/screens/admin_screen.dart`, Leitungsteam only) —
-  list/create KCs; per KC the Gemeinden (list/create) and pending
-  Verantwortlichen self-registrations (`GET /onboarding/requests`,
-  approve / reject).
+  list/create KCs; per KC:
+  - Gemeinden (list/create); each opens **Teamer-Verwaltung**
+    (`teamer_admin_screen.dart`): local Teamer accounts + group-link / email
+    invites.
+  - **Workshop-Wahlen** (`wahl_admin_screen.dart`): create Wahlen, add
+    workshops, run the assignment, view the result table.
+  - pending Verantwortlichen self-registrations (approve / reject).
+- **Als Verantwortliche/r registrieren**
+  (`verantwortliche_register_screen.dart`) — shown on the home screen to a
+  logged-in Authentik user without a membership: enter a KC invite code,
+  pick a Gemeinde, submit; a Leitungsteam member then approves.
 - **Workshop-Wahl** (`lib/screens/wahl_screen.dart`, guests) — two tabs:
   *Wünsche* (`GET /wahl/guest/overview`, tap workshops in order, max 3,
   `POST /wahl/:id/teilnehmer`) and *Ergebnis* (`GET /wahl/guest/results` —