Version history, notes on highlights and bookmarks, "you've studied this", prayer journal

- Earlier versions of a study: the server keeps compressed copies (about one per ten minutes of
  editing, the latest 30); Export shows what differs and puts one back (the replaced copy is kept)
- Notes on highlights and bookmarks: synced, merged without loss, in exports and backups
- Reader verse panel lists your studies and chunks that cover the verse, and opens them
- Prayer journal: requests, who for, linked verses, days prayed, answers; synced, in backups
  and the account export; daily prayer reminder through ntfy
- TODO.md lists the ideas not built yet

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

TODO.md

@@ -0,0 +1,30 @@
+# To do
+
+Ideas for the app that haven't been built yet, roughly in the order I'd do them. Tick one off when it ships.
+
+## Running it and keeping it safe
+- [ ] **Email (SMTP).** A mail setting for password resets and invite links, so they don't depend on the ntfy topic. Also lets a
+      co-teacher get their invite by email. Needs a `SMTP_URL`-style setting and a fallback to today's behaviour.
+- [ ] **Passkeys and a device list.** Sign in with Face ID or a fingerprint (WebAuthn); show where you're signed in with
+      "sign out other devices"; optionally a login alert through ntfy.
+- [ ] **Server health page for the admin.** Last backup, disk use, failed notifications, recent sign-in failures, and a
+      "restore a snapshot" button (snapshots already exist under `DATA_DIR/backups`).
+- [ ] **Checks on every push.** Run tests and lint on the Gitea server, plus a few real-browser tests (Playwright) for sign-in,
+      creating a study and syncing; so far everything is tested in simulation.
+- [ ] **Split `server/index.js`** (now about 1,100 lines) into one file per area (auth, projects, sharing, reader data, admin).
+
+## Teaching together
+- [ ] **Comments between co-teachers.** Notes on a chunk addressed to the other person, instead of editing each other's text.
+- [ ] **Live updates and "who's here".** A co-teacher's changes appear within seconds, with a marker like "Sam is on chunk 3"
+      (server-sent events or short polling). Today changes arrive when the tab regains focus or every couple of minutes.
+- [ ] **Ask Claude inside the app.** Draft discussion questions, tighten an outline point, summarise notes, using the owner's own
+      API key kept on the server. The Claude prompts today are copy-and-paste.
+
+## Reading
+- [ ] **Read-aloud with highlighting.** The device's voice reads the chapter and the verse being read is highlighted; useful for
+      the BSB and NET, which have no audio.
+- [ ] **Cross-reference map.** A picture of the links between chapters, from IQ Bible's reference graph (needs the IQ Bible key).
+
+## Decided against, for now
+- Scripture memory (verse practice with spaced review).
+- Extra-biblical books (Enoch, Maccabees) and non-standard canons.