VoxIP Kiosk OS 1.0.0: Raspberry Pi kiosk with web management

Chromium kiosk without a desktop for the Raspberry Pi 3, a Flask web
interface on port 8080 (kiosk, system and network management), a
restricted root helper, network changes with automatic rollback, a
healthcheck timer, install/update/uninstall scripts and a pi-gen image
build.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

www/offline.html

@@ -0,0 +1,56 @@
+<!doctype html>
+<html lang="nl">
+<head>
+  <meta charset="utf-8">
+  <title>Geen verbinding</title>
+  <link rel="stylesheet" href="kiosk.css">
+</head>
+<body>
+  <main class="stage" id="stage">
+    <img class="logo" src="logo.svg" alt="">
+    <div class="device" id="device"></div>
+    <h1>De informatie is tijdelijk niet beschikbaar</h1>
+    <p id="detail">Er is op dit moment geen verbinding met de server.</p>
+    <div class="clock" id="clock">--:--</div>
+    <div class="date" id="date"></div>
+    <div class="status"><span class="dot" aria-hidden="true"></span><span id="status">Automatisch opnieuw verbinden…</span></div>
+  </main>
+  <script>
+    const params = new URLSearchParams(location.search);
+    const fmtTime = new Intl.DateTimeFormat("nl-NL", { hour: "2-digit", minute: "2-digit" });
+    const fmtDate = new Intl.DateTimeFormat("nl-NL", { weekday: "long", day: "numeric", month: "long", year: "numeric" });
+    document.getElementById("device").textContent = params.get("name") || "";
+    const host = params.get("host");
+    const reason = params.get("reason");
+    if (host) {
+      document.getElementById("detail").textContent =
+        "Geen verbinding met " + host + (reason ? " (" + reason + ")" : "") + ".";
+    }
+    const since = Number(params.get("since")) * 1000;
+
+    function tick() {
+      const now = new Date();
+      document.getElementById("clock").textContent = fmtTime.format(now);
+      const date = fmtDate.format(now);
+      document.getElementById("date").textContent = date.charAt(0).toUpperCase() + date.slice(1);
+      if (since) {
+        const minutes = Math.floor((now - since) / 60000);
+        document.getElementById("status").textContent = minutes >= 1
+          ? "Offline sinds " + fmtTime.format(new Date(since)) + " — automatisch opnieuw verbinden…"
+          : "Automatisch opnieuw verbinden…";
+      }
+    }
+    tick();
+    setInterval(tick, 1000);
+
+    // Shift the content slowly to avoid burn-in on screens that stay offline for long.
+    let step = 0;
+    setInterval(() => {
+      step = (step + 1) % 8;
+      const dx = [0, 12, 24, 12, 0, -12, -24, -12][step];
+      const dy = [0, -8, 0, 8, 0, -8, 0, 8][step];
+      document.getElementById("stage").style.transform = "translate(" + dx + "px," + dy + "px)";
+    }, 60000);
+  </script>
+</body>
+</html>