Expand README.md and frontend/README.md with fuller project description

Both were thin/stale for what the project has actually grown into (the
frontend README still framed things as "Phase 1-6" and listed maybe a
third of the current src/ tree). Added a Features section and tech-stack
summary to the root README, and refreshed the frontend README's layout
listing to match what's actually in src/ today.

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

README.md

@@ -1,25 +1,62 @@
 # DS Chat
 
-A web-based team chat service (Mattermost-style, no threaded conversations),
-invite-only. See [ARCHITECTURE.md](ARCHITECTURE.md) for the full system design
-and phased build plan.
+A self-hosted, real-time team chat service in the spirit of Slack/Discord/
+Mattermost (channel-based, no threaded conversations) — built from scratch
+as a full-stack solo project, running in production on my own infrastructure
+rather than as a demo. Invite-only: there's no public sign-up, every account
+comes from an admin invite or a room invite. See
+[ARCHITECTURE.md](ARCHITECTURE.md) for the full system design and phased
+build plan.
 
-**Phase 1**: auth, open-room CRUD, and single-instance WebSocket chat, backend
-+ a minimal frontend. **Phase 2**: private rooms, room roles (owner/admin/
-member), and room invites — backend only, see below. Later phases (push
-notifications, Redis fan-out, the admin portal, the bot/extension system, and
-production deployment) are tracked as issues in the repo's issue tracker,
-prioritized.
+## Features
+
+- **Auth & accounts** — session-based auth, invite-only signup (admin-issued
+  site invites or room invites, both delivered by email), password reset,
+  per-user light/dark/midnight/sunset presets plus a live theme builder for
+  fully custom, named, savable color themes.
+- **Rooms** — open and private rooms, owner/admin/member roles, invites,
+  room browsing/search, file/image galleries per room.
+- **Real-time chat** — WebSocket-based messaging with automatic reconnect
+  and backoff, Markdown rendering, @mentions with autocomplete and inline
+  highlighting, emoji reactions, message editing, image and file
+  attachments (drag-and-drop, paste, or picker) with inline previews for
+  images/PDFs/text/Markdown, unread indicators, and presence (online/away/
+  offline, with a manual "appear offline" override).
+- **Notifications** — Web Push for offline/backgrounded members, with
+  per-type opt-in/out (mentions vs. all messages), plus in-app unread
+  badges.
+- **PWA** — installable, offline-capable (cached room/message data, a
+  dedicated offline banner), with automatic update detection that prompts
+  a reload as soon as a new deploy goes live.
+- **Admin portal** — user management, site invites, SMTP configuration,
+  audit log, and management of the bot/webhook system below.
+- **Bots & integrations** — scoped API tokens for bot accounts, incoming
+  webhooks (post into a room from an external system) and outgoing webhooks
+  (signed HMAC event delivery on message create/update), all with SSRF
+  protection on any admin-supplied external URL.
+- **Scale-out** — Redis-backed pub/sub for WebSocket fan-out and presence,
+  so the app runs across multiple horizontally-scaled instances rather than
+  a single process.
+
+## Tech stack
+
+- **Backend**: Python, FastAPI, SQLAlchemy 2.0 (fully async), PostgreSQL,
+  Redis, Alembic migrations, argon2 password hashing, Web Push (VAPID).
+- **Frontend**: React 19, TypeScript, Vite, a hand-rolled WebSocket client
+  with reconnect/backoff and visibility-aware presence, a PWA service
+  worker (Workbox) for offline caching and push.
+- **Deployment**: two bare Debian 13 servers (app + DB/cache), no
+  containers — see [DEPLOYMENT.md](DEPLOYMENT.md).
 
 ## Structure
 
-- [`backend/`](backend/) — FastAPI + SQLAlchemy 2.0 (async) + PostgreSQL. See
-  [`backend/README.md`](backend/README.md) for local setup, migrations, how to
-  create a user (site registration is invite-only — no public sign-up
-  endpoint), and the Phase 2 room-roles/invites API.
-- [`frontend/`](frontend/) — React + Vite PWA (login, room list, chat view).
-  Still Phase-1-only: it doesn't yet call any of the Phase 2 endpoints. A UI
-  redesign is happening separately; frontend work resumes once that lands.
+- [`backend/`](backend/) — FastAPI + SQLAlchemy 2.0 (async) + PostgreSQL +
+  Redis. See [`backend/README.md`](backend/README.md) for local setup,
+  migrations, how to create a user (site registration is invite-only — no
+  public sign-up endpoint), and the full API surface.
+- [`frontend/`](frontend/) — React + Vite PWA covering the full feature set:
+  auth, room roles/invites, chat, offline caching, push notifications, and
+  the admin portal. See [`frontend/README.md`](frontend/README.md).
 
 ## Quickstart
 
@@ -29,7 +66,10 @@ docker run -d --name ds-chat-postgres \
   -e POSTGRES_USER=ds_chat -e POSTGRES_PASSWORD=ds_chat -e POSTGRES_DB=ds_chat \
   -p 5432:5432 postgres:16-alpine
 
-# 2. Backend
+# 2. Redis (required — used for cross-instance WebSocket fan-out and presence)
+docker run -d --name ds-chat-redis -p 6379:6379 redis:7-alpine
+
+# 3. Backend
 cd backend
 python3 -m venv .venv
 .venv/bin/pip install -e ".[dev]"
@@ -38,7 +78,7 @@ cp .env.example .env   # then set SESSION_SECRET
 .venv/bin/python -m app.cli create-user alice alice@example.com "some-password"
 .venv/bin/uvicorn app.main:app --reload &
 
-# 3. Frontend (in another shell)
+# 4. Frontend (in another shell)
 cd frontend
 npm install
 npm run dev