Add music visualizer for music, radio, podcasts and audiobooks

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01UaC9HmtHMdRP8dAbN4wAKj

README.md

@@ -100,6 +100,12 @@ e.g. hub.necloud.us. Settings: `SEAFILE_URL`, `ONLYOFFICE_URL` env vars in docke
   - Message text is shown in a sandboxed frame with no scripts, and pictures from the internet stay hidden until you press Show pictures. Not included: a combined inbox across accounts (switch account at the top), message previews in the list for Gmail/iCloud, drafts autosave, contacts, Microsoft 365 work accounts, other IMAP providers (easy to add the same way).
   **One-time Outlook.com setup** (step by step, with troubleshooting, in [docs/mail-setup.md](docs/mail-setup.md); needs a free Microsoft account and takes five minutes): go to entra.microsoft.com -> App registrations -> New registration. Name it NE Hub; supported account types **Personal Microsoft accounts only**; Redirect URI: platform **Web**, value `<your hub address>/api/mail/callback` (for example `https://hub.necloud.us/api/mail/callback`; it must match `PUBLIC_URL` exactly). Then API permissions -> Add -> Microsoft Graph -> Delegated: `Mail.ReadWrite`, `Mail.Send`, `User.Read`, `offline_access`. Copy the **Application (client) ID** and paste it, with the secret, into **Settings -> Microsoft app (admin)** (or set `MS_CLIENT_ID` / `MS_CLIENT_SECRET` in the environment, which win). If you registered it as a Web app, also make a client secret (Certificates & secrets) and put its value in `MS_CLIENT_SECRET`; if you used platform "Mobile and desktop applications" instead, no secret is needed. Leave `MS_CLIENT_ID` empty to switch Mail off. (The old bundled Cypht webmail and its `nehub-cypht` volume are gone; you can delete that volume.) Connecting from the installed iPhone/iPad app may open Microsoft's page in Safari; if the app does not notice, reopen it.
 
+## Visualizer
+
+Tap **Visuals** on the Now Playing sheet, the Music card or the Journey FM card for a full-screen picture that moves with the sound: Rings (cover art in the middle), Bars, Waves, Aurora and Sparks. It works for music, radio, podcasts and audiobooks, picks a calm look for speech, and takes its colours from the cover. Tap the picture to hide the buttons; Esc closes it. The screen stays awake while it is open.
+
+It listens to the sound the browser is playing. Where it cannot (iPhone Safari, or audio that comes from another site such as Verse By Verse and LibriVox), it falls back to an "ambient" animation that still keeps time with play and pause, and the top of the screen says which mode is on.
+
 ## Install on iPhone / iPad (PWA)
 
 Open the site in **Safari** (it must be the `https://` address), tap **Share -> Add to Home Screen**. The home-screen app has proper