move const CONFIG to json file and add documentation in README.md

README.md

@@ -2,6 +2,21 @@
 
 A small html/js project to nudge a user to use the desktop client for Jitsi.
 
+## Configuration
+
+All settings live in `assets/config.json`, loaded at startup. The launcher stays
+up but links break if the file is missing or malformed.
+
+| Parameter | Description |
+| --- | --- |
+| `jitsiLauncher` | Domain of this Jitsi launcher. Used for the meeting URLs created by the meeting creator (Nextcloud, adhoc link). |
+| `jitsiHost` | Jitsi domain. Used for the browser fallback URL, the desktop protocol URL and the UID of generated ICS files. |
+| `nextcloudBase` | Nextcloud instance used by the "Create in Nextcloud" button (calendar event creation). |
+| `launchTimeout` | Timeout in ms before the browser fallback is shown after trying to start the jitsi-meet-electron client. |
+| `backgroundImage` | Path to the page background image. Empty: no background. |
+| `logo` | Path to the logo shown in the logo bar. Empty: logo bar stays hidden. |
+| `downloads` | Download URLs for the jitsi-meet clients, shown in the fallback view per detected OS: `windows`, `macos`, `linux`, `ios`, `android`. |
+
 ## Third-party assets
 
 - `assets/lib/ua-parser.min.js` — [ua-parser-js](https://github.com/faisalman/ua-parser-js) v2.0.10, © Faisal Salman, licensed under AGPL-3.0.