MCP server, timeline embeds, YouTube playback, and visual timeline search

✅ New functionalities

1. MCP server to manage timelines and events from supported AI assistants (including Cursor and ChatGPT).
2. OAuth connection flow for authorizing MCP clients, with branded sign-in and consent screens.
3. Personal access token API for programmatic timeline and event access.
4. Embed public timelines on external websites with a shareable embed snippet.
5. Click-to-play YouTube videos on event pages and play-icon previews on the timeline view.

🎛️ Improvements

1. Adaptive layout when many multi-day events stack on the same dates.
2. Sticky date axis while scrolling wide timelines horizontally; viewport-aware column sizing with soft alignment.
3. Event-lines extend left of the content column for a fuller visual canvas; active lanes prioritized over concluded ones.
4. Secondary event titles peek through lane gaps; clearer highlight tooltips and softer dimming when focusing one event.
5. Timeline search dims non-matching periods and jumps to each match, with refined controls and smarter unit filtering.
6. Event header prev/next navigation and a contextual back link from timeline view.
7. Public board defaults to sorting by recently updated timelines.
8. OAuth consent shows which TIMELINEZ account you are authorizing, with an option to switch.

🐞 Bug Fixing

1. Sticky action bars after rotating to landscape and unwanted gap below the navbar.
2. Event-line overlaps at month/year boundaries on long-running timelines.
3. Faster rendering of overlapping months on large timelines.
4. Rich-text editor: blockquotes with attachments, stray empty rows when editing, bracket display in note previews, and YouTube preview while editing.
5. Clearer event show/edit page headings.
6. Search row visibility and gap markers on dense timeline layouts.