feat: add ntfy push notifications for daily digest and per-prayer reminders

- Server-side cron (node-cron) checks every minute for scheduled notifications
- Daily digest: sends all active prayers as a summary at a configured time
- Per-prayer reminders: pick days of the week per prayer; fires at configured time
- Settings panel in UI to configure ntfy topic, digest time, reminder time
- Test notification button to verify ntfy is working
- Settings stored in data/settings.json (persisted alongside prayers)

src/App.css

@@ -912,3 +912,136 @@ mark.highlight {
   font-size: 0.92rem;
   line-height: 1.4;
 }
+
+/* Settings panel */
+.settings-btn {
+  margin-top: 0.5rem;
+  font-size: 0.85rem;
+}
+
+.settings-panel {
+  background: var(--surface);
+  border: 1px solid var(--border);
+  border-radius: 10px;
+  padding: 1.25rem;
+  box-shadow: var(--shadow);
+  margin-bottom: 1.5rem;
+}
+
+.settings-title {
+  font-size: 1.1rem;
+  font-weight: normal;
+  margin-bottom: 0.5rem;
+}
+
+.settings-desc {
+  font-size: 0.88rem;
+  color: var(--text-muted);
+  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
+  margin-bottom: 1rem;
+  line-height: 1.5;
+}
+
+.settings-desc a { color: var(--primary); }
+
+.settings-form {
+  display: flex;
+  flex-direction: column;
+  gap: 0.85rem;
+}
+
+.settings-label {
+  display: flex;
+  flex-direction: column;
+  gap: 0.3rem;
+  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
+  color: var(--text-muted);
+  text-transform: uppercase;
+  letter-spacing: 0.05em;
+  font-size: 0.75rem;
+}
+
+.settings-input {
+  border: 1px solid var(--border);
+  border-radius: 6px;
+  padding: 0.5rem 0.75rem;
+  background: var(--bg);
+  color: var(--text);
+  font-family: inherit;
+  font-size: 0.95rem;
+  outline: none;
+  transition: border-color 0.15s;
+}
+
+.settings-input:focus { border-color: var(--primary); }
+
+.settings-hint {
+  font-size: 0.78rem;
+  color: var(--text-muted);
+  text-transform: none;
+  letter-spacing: 0;
+  font-style: italic;
+}
+
+.settings-actions {
+  display: flex;
+  gap: 0.5rem;
+  align-items: center;
+  flex-wrap: wrap;
+}
+
+.settings-msg {
+  font-size: 0.85rem;
+  color: var(--answered);
+  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
+}
+
+/* Reminder day picker */
+.reminder-row {
+  display: flex;
+  align-items: center;
+  gap: 0.75rem;
+  padding-top: 0.5rem;
+  border-top: 1px solid var(--border);
+  flex-wrap: wrap;
+}
+
+.reminder-label {
+  font-size: 0.8rem;
+  color: var(--text-muted);
+  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
+  white-space: nowrap;
+}
+
+.day-picker {
+  display: flex;
+  gap: 0.3rem;
+}
+
+.day-btn {
+  width: 2rem;
+  height: 2rem;
+  border-radius: 50%;
+  border: 1px solid var(--border);
+  background: var(--bg);
+  color: var(--text-muted);
+  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
+  font-size: 0.72rem;
+  cursor: pointer;
+  transition: background 0.12s, color 0.12s, border-color 0.12s;
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  padding: 0;
+}
+
+.day-btn:hover {
+  border-color: var(--primary);
+  color: var(--primary);
+}
+
+.day-btn.active {
+  background: var(--primary);
+  color: #fff;
+  border-color: var(--primary);
+}