Notes tab: shared and private notes and checklists; icon-only menu rail on short windows

- notes.js and the Notes tab: private, family or chosen-people sharing; checklist items change one at a time (no overwrites), with who ticked them; open lists refresh live; stale text edits are refused
- Pin, colour, archive, search, filters, ready-made lists, Share to Chat, send open items to Tasks
- The narrow menu rail shows icons only (names on hover) when the window is too short for labels
- Roadmap and README updated

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

README.md

@@ -182,3 +182,7 @@ Files are kept in the data folder under `mystore/` (up to 1 GB each; extensions
 
 **Chat** (turn it on per person in the admin screen): the family's own messenger, with the same look as the Signal tab. Direct chats and groups between people who have an account here, text with links and emoji, attachments (up to 100 MB each; pictures, audio and video show in the chat), replies, reactions, edit and delete for everyone, unread counts on the menu and the tab title, search (chats and messages), drafts that survive closing the app, mute and archive, live delivery while the app is open and a phone push when it is not (the same notification devices as reminders, and muted chats stay quiet). Messages and files are kept readable on this server in `data/chat`; end-to-end encryption is not built. Also: sent, delivered and read ticks (everyone, in a group), typing and who is online, disappearing messages (a timer per chat), @mentions (a mentioned person is alerted even in a muted group), pinned messages, forwarding, voice messages with a waveform, link previews (the server reads the page, so devices never contact the site), polls (single or multiple choice, with who voted), an emoji picker, turn a message into a task, a shopping item or a calendar event, *Share to Chat* from a recipe or a song, quiet hours for phone alerts, and a family announcement on Home that an admin posts from Chat settings. Not built: a GIF picker, sharing a location (the hub blocks location access), and a parent setting a child's quiet hours (see `docs/v2-roadmap.md`).
 
+**Notes** (turn it on per person): notes and checklists that are private, shared with the whole family, or shared with chosen people. Anyone it is shared with can edit it. Checklist items change one at a time (tick, add, edit, remove), so two people ticking the same list never overwrite each other, ticked items say who ticked them, and an open list follows other people's changes every few seconds. Text edits are checked against a revision, so a stale edit is refused instead of overwriting someone else's. Pin, colour, archive, search and filters (lists, notes, mine, shared, archived), ready-made lists (grocery, packing, weekend to-do), *Share to Chat*, and *Send the open items to Tasks*. Only the person who made a note (or an admin) changes who it is shared with or deletes it.
+
+On a tablet or with the menu collapsed, the menu rail shows icons only (the name appears on hover) when the window is not tall enough for a label under every icon.
+