Make legal notice link configurable

The legal notice link in the navbar was hardcoded to the
bnvb website. Deployments without that legal notice showed
a dead link to a foreign site.

Move the URL into assets/config.json (legalNotice), like
the Nextcloud and adhoc buttons. The link stays hidden
unless the entry is configured.

assets/config.json.sample

@@ -2,6 +2,7 @@
   "jitsiLauncher": "server.domain.tld/subdir",
   "jitsiHost": "jit.si",
   "nextcloudBase": "https://cloud.domain.tld",
+  "legalNotice": "https://www.domain.tld/legal-notice",
   "allowAdhocMeetings": true,
   "launchTimeout": 2000,
   "backgroundImage": "path/to/backgroundimage",

assets/launch.js

@@ -12,6 +12,20 @@
 let CONFIG = {};
 const CONFIG_URL = "assets/config.json";
 
+/*
+ * localStorage is scoped per origin, not per path.
+ * Prefix keys with the app directory so parallel
+ * instances (e.g. meet.bnvb.eu/i and /p) stay
+ * independent.
+ *
+ * "/p/launch.html" becomes "/p/"
+ */
+const STORAGE_PREFIX =
+  window.location.pathname.replace(/[^/]*$/, "");
+
+const LANGUAGE_KEY = STORAGE_PREFIX + "jitsiLauncherLanguage";
+const THEME_KEY = STORAGE_PREFIX + "jitsiLauncherTheme";
+
 /* ============================================================
  * Translations
  * ============================================================
@@ -34,7 +48,7 @@ function detectLanguage() {
    * Saved language choice takes precedence.
    */
   try {
-    const saved = localStorage.getItem("jitsiLauncherLanguage");
+    const saved = localStorage.getItem(LANGUAGE_KEY);
 
     if (saved && TRANSLATIONS[saved]) {
       return saved;
@@ -179,7 +193,7 @@ function setLanguage(language) {
   translation = TRANSLATIONS[language];
 
   try {
-    localStorage.setItem("jitsiLauncherLanguage", language);
+    localStorage.setItem(LANGUAGE_KEY, language);
   } catch (error) {
     /*
      * localStorage can be blocked, e.g. in private mode.
@@ -225,8 +239,6 @@ function closeNavMenu() {
  * ============================================================
  */
 
-const THEME_KEY = "jitsiLauncherTheme";
-
 function savedTheme() {
   try {
     const saved = localStorage.getItem(THEME_KEY);
@@ -370,6 +382,23 @@ function applyAdhocButton() {
   createAdhocButton.classList.remove("hidden");
 }
 
+/* ============================================================
+ * LEGAL NOTICE LINK
+ * ============================================================ */
+
+/*
+ * Only show if a legal notice URL is configured
+ * (CONFIG.legalNotice in assets/config.json).
+ */
+function applyLegalNoticeLink() {
+  if (!CONFIG.legalNotice || !legalNoticeLink) {
+    return;
+  }
+
+  legalNoticeLink.href = CONFIG.legalNotice;
+  legalNoticeLink.classList.remove("hidden");
+}
+
 /* ============================================================
  * DOM elements
  * ============================================================
@@ -420,6 +449,7 @@ const copyAdhocLinkButton = document.getElementById("copyAdhocLinkButton");
 const navbar = document.querySelector(".navbar");
 const navToggle = document.getElementById("navToggle");
 const navActions = document.getElementById("navActions");
+const legalNoticeLink = document.getElementById("legalNoticeLink");
 
 /* Language menu DOM elements */
 const langMenu = document.getElementById("langMenu");
@@ -1609,6 +1639,7 @@ async function start() {
   applyFavicons();
   applyNextcloudButton();
   applyAdhocButton();
+  applyLegalNoticeLink();
 
   await loadTranslations();
 

launch.html

@@ -30,7 +30,7 @@
         </svg>
       </button>
       <div id="navActions" class="nav-actions">
-      <a class="button secondary" href="https://www.bnvb-ingenieure.de/impressum" target="_blank" rel="noopener noreferrer" data-i18n="legal_notice">
+      <a id="legalNoticeLink" class="button secondary hidden" href="#" target="_blank" rel="noopener noreferrer" data-i18n="legal_notice">
         Legal Notice
       </a>
       <a class="button secondary" href="https://git.bnvb.eu/stefan.tollkuehn/jitsi-launch" target="_blank" rel="noopener noreferrer" data-i18n="source">