Initial implementation of Sahsa Clock

Pygame framebuffer clock for Le Potato (ARM Debian) with aiohttp webhook server.
Renders 12-hour clock directly to /dev/fb0 (no X11/Wayland). Supports full-screen
message overlays pushed via a browser dashboard or Bearer-token API. Includes
first-run setup wizard, session-based dashboard auth, bcrypt password storage,
per-IP rate limiting, and systemd service unit.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

dashboard/app.js

@@ -0,0 +1,130 @@
+'use strict';
+
+const msgTextarea = document.getElementById('msg');
+const charNum     = document.getElementById('char-num');
+const sendBtn     = document.getElementById('send-btn');
+const clearBtn    = document.getElementById('clear-btn');
+const statusDot   = document.getElementById('status-dot');
+const statusText  = document.getElementById('status-text');
+
+// ── Character counter ────────────────────────────────────────────────────────
+
+msgTextarea.addEventListener('input', () => {
+  charNum.textContent = msgTextarea.value.length;
+});
+
+// ── Duration helper ──────────────────────────────────────────────────────────
+
+function getSelectedDuration() {
+  const checked = document.querySelector('input[name="duration"]:checked');
+  return checked ? parseInt(checked.value, 10) : 60;
+}
+
+// ── Auth redirect helper ─────────────────────────────────────────────────────
+
+function handleUnauth(status) {
+  if (status === 401) {
+    window.location.href = '/login';
+    return true;
+  }
+  return false;
+}
+
+// ── Send message ─────────────────────────────────────────────────────────────
+
+async function sendMessage() {
+  const text = msgTextarea.value.trim();
+  if (!text) {
+    msgTextarea.focus();
+    return;
+  }
+
+  const duration = getSelectedDuration();
+  const body = { text };
+  if (duration === 0) {
+    body.persist = true;
+  } else {
+    body.duration = duration;
+  }
+
+  sendBtn.disabled = true;
+  try {
+    const res = await fetch('/dashboard/message', {
+      method: 'POST',
+      headers: { 'Content-Type': 'application/json' },
+      body: JSON.stringify(body),
+    });
+
+    if (handleUnauth(res.status)) return;
+
+    if (res.ok) {
+      msgTextarea.value = '';
+      charNum.textContent = '0';
+      await refreshStatus();
+    } else {
+      const err = await res.text();
+      setStatus(false, `Error: ${err}`);
+    }
+  } catch {
+    setStatus(false, 'Could not reach server.');
+  } finally {
+    sendBtn.disabled = false;
+  }
+}
+
+// ── Clear message ────────────────────────────────────────────────────────────
+
+async function clearMessage() {
+  try {
+    const res = await fetch('/dashboard/message', { method: 'DELETE' });
+    if (handleUnauth(res.status)) return;
+    if (res.ok) {
+      await refreshStatus();
+    }
+  } catch {
+    setStatus(false, 'Could not reach server.');
+  }
+}
+
+// ── Status polling ───────────────────────────────────────────────────────────
+
+function setStatus(active, message) {
+  statusDot.className = 'status-dot' + (active ? ' active' : '');
+  statusText.textContent = message;
+}
+
+async function refreshStatus() {
+  try {
+    const res = await fetch('/dashboard/status');
+    if (handleUnauth(res.status)) return;
+
+    const data = await res.json();
+
+    if (data.active) {
+      let detail = '';
+      if (data.persistent) {
+        detail = ' — until cleared';
+      } else if (data.remaining_seconds !== null) {
+        const secs = Math.round(data.remaining_seconds);
+        const mins = Math.floor(secs / 60);
+        detail = mins > 0
+          ? ` — ${mins}m ${secs % 60}s remaining`
+          : ` — ${secs}s remaining`;
+      }
+      setStatus(true, `Showing: "${data.text}"${detail}`);
+    } else {
+      setStatus(false, 'Screen is showing the clock.');
+    }
+  } catch {
+    setStatus(false, 'Could not reach server.');
+  }
+}
+
+// ── Wire up events ───────────────────────────────────────────────────────────
+
+sendBtn.addEventListener('click', sendMessage);
+clearBtn.addEventListener('click', clearMessage);
+
+// Initial status fetch, then poll every 5 seconds
+refreshStatus();
+setInterval(refreshStatus, 5000);