Fix plan days with no chapters, add a way out of ink mode, harden ntfy reminders

Plans can no longer have more days than chapters (existing ones heal), and
opening a plan never strands the Reader on an empty day. The Reader shows
Done drawing while inking (Escape also exits). Reminders use the user's own
timezone, send within a 3 hour grace window, and Settings has a Send test
notification button.

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

server/db.js

@@ -74,6 +74,11 @@ export function initDb() {
     `);
   }
 
+  // Reminders fire at the user's own local time, so remember their timezone.
+  if (!userCols.some((c) => c.name === 'reminder_tz')) {
+    db.exec('ALTER TABLE users ADD COLUMN reminder_tz TEXT');
+  }
+
   // Older databases predate shareable read-only links.
   if (!projectCols.some((c) => c.name === 'share_token')) {
     db.exec('ALTER TABLE projects ADD COLUMN share_token TEXT');
@@ -146,7 +151,7 @@ const USER_SELECT = `
          totp_secret AS totpSecret, totp_enabled AS totpEnabled, backup_codes AS backupCodesRaw,
          podcast_name AS podcastName,
          ntfy_url AS ntfyUrl, ntfy_topic AS ntfyTopic, reminder_time AS reminderTime,
-         reminder_enabled AS reminderEnabled, last_reminder_date AS lastReminderDate
+         reminder_enabled AS reminderEnabled, last_reminder_date AS lastReminderDate, reminder_tz AS reminderTz
   FROM users
 `;
 
@@ -182,18 +187,18 @@ export function setPodcastName(userId, podcastName) {
 // ---------------------------------------------------------------------------
 
 /** Saves a user's ntfy reminder settings ({ ntfyUrl, ntfyTopic, reminderTime, reminderEnabled }). */
-export function setReminderSettings(userId, { ntfyUrl, ntfyTopic, reminderTime, reminderEnabled }) {
+export function setReminderSettings(userId, { ntfyUrl, ntfyTopic, reminderTime, reminderEnabled, reminderTz }) {
   db.prepare(`
-    UPDATE users SET ntfy_url = ?, ntfy_topic = ?, reminder_time = ?, reminder_enabled = ?
+    UPDATE users SET ntfy_url = ?, ntfy_topic = ?, reminder_time = ?, reminder_enabled = ?, reminder_tz = ?
     WHERE id = ?
-  `).run(ntfyUrl || null, ntfyTopic || null, reminderTime || null, reminderEnabled ? 1 : 0, userId);
+  `).run(ntfyUrl || null, ntfyTopic || null, reminderTime || null, reminderEnabled ? 1 : 0, reminderTz || null, userId);
 }
 
 /** Every account with reminders turned on and a topic configured — checked once a minute. */
 export function getUsersWithRemindersEnabled() {
   return db.prepare(`
     SELECT id, email, ntfy_url AS ntfyUrl, ntfy_topic AS ntfyTopic, reminder_time AS reminderTime,
-           last_reminder_date AS lastReminderDate
+           last_reminder_date AS lastReminderDate, reminder_tz AS reminderTz
     FROM users
     WHERE reminder_enabled = 1 AND ntfy_topic IS NOT NULL AND reminder_time IS NOT NULL
   `).all();