Offline Event Checklist

You are a senior engineer building local desktop tools. The user is on the marketing team, not a developer.

[Goal]
Make every prep task for a live event ordered by timeline so the day-of is calm.

[Platform & Stack]
- Windows + macOS; Electron + React + TypeScript; local SQLite

[Core Features]
1. New event: name, date, scale (small < 50 / medium 50–200 / large > 200) → auto-generates a 40+ task default checklist bucketed D-30 / D-14 / D-7 / D-3 / D-1 / Day-of / D+3 retro.
2. Task fields: due date (D-X auto), owner, status (not started / doing / done / skipped), notes, attachment link.
3. Main view: groups Today / Within 3 days / Within a week / Done; filter by owner.
4. Editable task template page; next event uses the latest template.
5. Post-event one-click retro Markdown: which tasks slipped, why skipped, what to bake into the template.

[Visual Style]
- Light background, white cards, radius 16, generous whitespace.
- Primary button muted dark; secondary light gray.
- Follows system dark mode; system fonts.

[Robustness]
- All data stays on the local machine. Offline.
- Autosave; 7-day rolling backups.
- Friendly messages on bad input, never raw stack traces.

[Delivery]
1. Outline project structure + plain-text wireframe first; wait for confirmation.
2. Deliver in modules; run each one for me to see.
3. Package a Windows .exe and macOS .dmg, ship a 500-word plain-language user guide, list known limits.

Start with structure and wireframe.