docs: reflect Postgres, migration, and the Flutter client

Root README + plan updated: local PostgreSQL 16 + first Prisma migration,
end-to-end guest-flow verification, and the started Flutter client
(client/app/, web target). Phase 7 marked in progress with the remaining
client work spelled out.

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

README.md

@@ -12,12 +12,13 @@ for the full architecture and phased roadmap.
   sharing, chat, local/cloud sync). See [backend/README.md](backend/README.md)
   for setup. Also serves the web client (see below) directly, so it's the
   single entry point for the web experience.
+- `client/app/` — the Flutter client (single codebase; **web** target
+  enabled, mobile/desktop can be added later). Login (guest / local Teamer /
+  invite redemption), role-aware home, guest Workshop-Wahl, file list,
+  read-only chat. See [client/app/README.md](client/app/README.md).
 - `client/web/` — minimal dependency-free HTML/CSS/JS placeholder web
-  client (guest join, Wahl submission, file list, chat) exercising the real
-  API, served by the backend at `/`. Will be replaced by the Flutter web
-  build once Flutter is available.
-- `client/` (mobile/desktop) — planned Flutter app, not yet scaffolded
-  (Flutter is not installed in this environment).
+  client, served by the backend at `/`. Superseded by the Flutter web build;
+  kept for now as a zero-dependency fallback.
 
 ## Status
 
@@ -50,12 +51,24 @@ cloud server's `/sync/ingest` + `/sync/export` endpoints (shared-secret
 authenticated, not user auth). No conflict resolution needed by design - the
 local server is the sole source of truth while an event is live.
 
-The backend now also serves the web client directly (static files from
-`client/web/`, API under `/api`), so the same process is the single entry
-point for the web experience.
+Since then: local (non-Authentik) Gemeinde Teamer accounts + invites
+(`teamer/`, `auth/team-login`), Gemeinde CRUD (`gemeinde/`), Gemeinde
+Verantwortliche self-registration with LT approval (`onboarding/`), JIT
+`User` provisioning on first Authentik login, LEITUNGSTEAM derived from the
+Authentik `groups` claim, and an email module (`mail/`, log-only by default,
+SMTP opt-in) that sends personal Teamer invites. First Prisma migration is
+in (`backend/prisma/migrations/`); the backend has been run end to end
+against a local PostgreSQL 16. `npm test` covers the assignment algorithm
+and the new auth/onboarding services (56 tests).
 
-Backend builds and boots cleanly (`npm run build`, `node dist/main.js`) but
-requires a real PostgreSQL database, Authentik instance, and Nextcloud/S3
-credentials (see `backend/.env.example`) to run end to end. Remaining: the
-Flutter clients (mobile/desktop; web has an interim plain-HTML client).
+Phase 7 (Flutter client) started: `client/app/` is a single Flutter
+codebase with the **web** target enabled — login (guest / local Teamer /
+invite redemption), role-aware home, guest Workshop-Wahl, file list,
+read-only chat. `flutter build web` and `flutter test` pass. Mobile/desktop
+targets, the Authentik Authorization-Code flow, WebSocket chat send, and LT
+admin screens are still to come.
+
+The backend also serves the interim `client/web/` placeholder at `/` (API
+under `/api`). Running end to end still needs a real Authentik instance and
+Nextcloud/S3 credentials (see `backend/.env.example`).