docs: final 1.0.0 documentation pass

README.md:
- Node prerequisite: v12+ → v22+
- Real-Time Updates: describe SSE push, remove polling/refresh-selector wording
- On-demand mode: update for SSE connect triggering poll
- API Endpoints: add /stream, /me, /csrf, /user-summary, /status, /cover-art
- Remove stale /api/qbittorrent proxy entry
- Docker tags: update to 1.0.x

SECURITY.md:
- Supported versions: add 1.0.x, retire 0.2.x
- CSP header: add style-src-attr 'unsafe-inline'
- Nginx example: add proxy_buffering off / proxy_read_timeout for SSE

Diagrams:
- seq-dashboard.puml: rewrite as SSE stream sequence (connect,
  initial payload, pushed updates, heartbeat, disconnect)
- seq-polling.puml: add SSE subscriber notification step after
  cache population
- state-ui.puml: replace Refresh Rate sub-state with SSE Connection
  state machine; update splash loading and logout transitions
- state-poller.puml: add Notifying SSE subscribers step in Polling state

package.json: bump to 1.0.0

README.md

@@ -51,7 +51,7 @@ SONARR_INSTANCES=[{"name":"main","url":"...","apiKey":"..."}]
 
 ## Prerequisites
 
-- **Docker** (recommended), or Node.js (v12+) for manual installation
+- **Docker** (recommended), or Node.js (v22+) for manual installation
 - At least one of: SABnzbd or qBittorrent
 - Sonarr (optional, for TV tracking)
 - Radarr (optional, for movie tracking)
@@ -141,8 +141,8 @@ services:
 | Tag | Description |
 |-----|-------------|
 | `latest` | Latest stable release |
-| `0.1` | Latest patch for the 0.1.x release line |
-| `0.1.0` | Specific version |
+| `1.0` | Latest patch for the 1.0.x release line |
+| `1.0.0` | Specific version |
 
 ### Updating
 
@@ -245,11 +245,12 @@ sofarr polls all configured services in the background and caches the results. D
 | `POLL_INTERVAL=10000` | Poll every 10 seconds. |
 | `POLL_INTERVAL=0` / `off` / `disabled` | No background polling. Data fetched on-demand when a user opens the dashboard, then cached for 30 seconds. |
 
-**On-demand mode** is useful for low-resource setups. When one user's browser refreshes, the fetched data is cached and served to all other users until it expires. A user with a faster refresh rate effectively keeps the cache warm for everyone.
+**On-demand mode** is useful for low-resource setups. When one user's browser opens the SSE stream it triggers a fresh poll; the fetched data is cached and served to all other connected clients until the next poll.
 
 ### Real-Time Updates
-- Auto-refresh every 5 seconds (configurable: 1s, 5s, 10s, or off)
+- **Server-Sent Events (SSE)** — the server pushes updates to the browser immediately after each poll cycle. No client-side timer; no wasted requests.
 - In-place DOM updates for smooth UI (no flickering)
+- Browser reconnects automatically on network interruption
 
 ### Download Information Displayed
 - **Progress bar** with visual completion percentage
@@ -267,18 +268,23 @@ sofarr polls all configured services in the background and caches the results. D
 ## API Endpoints
 
 ### Authentication
-- `POST /api/auth/login` - Login with Emby credentials
-- `POST /api/auth/logout` - Logout and clear session
+- `POST /api/auth/login` — Login with Emby credentials
+- `POST /api/auth/logout` — Logout and revoke session
+- `GET /api/auth/me` — Check current session
+- `GET /api/csrf` — Fetch a CSRF token
 
 ### Dashboard
-- `GET /api/dashboard/downloads` - Get all downloads for authenticated user
+- `GET /api/dashboard/stream` — **SSE stream**: pushes `{ user, isAdmin, downloads }` on every poll cycle
+- `GET /api/dashboard/user-downloads` — Single-request download fetch (no streaming)
+- `GET /api/dashboard/user-summary` — Per-user download counts (admin)
+- `GET /api/dashboard/status` — Server / polling / cache status (admin)
+- `GET /api/dashboard/cover-art` — Proxied cover art image
 
 ### Service APIs (proxy to your services)
-- `GET /api/sabnzbd/*` - SABnzbd API proxy
-- `GET /api/qbittorrent/*` - qBittorrent API proxy
-- `GET /api/sonarr/*` - Sonarr API proxy
-- `GET /api/radarr/*` - Radarr API proxy
-- `GET /api/emby/*` - Emby API proxy
+- `GET /api/sabnzbd/*` — SABnzbd API proxy
+- `GET /api/sonarr/*` — Sonarr API proxy
+- `GET /api/radarr/*` — Radarr API proxy
+- `GET /api/emby/*` — Emby API proxy
 
 ## Logging Levels