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>

public/index.html

@@ -93,6 +93,7 @@
 <script src="/file-actions.js"></script>
 <script src="/signal-view.js"></script>
 <script src="/chat-view.js"></script>
+<script src="/notes-view.js"></script>
 <script src="/mail.js"></script>
 <script src="/share.js"></script>
 <script src="/cast.js"></script>