Local calendar behavior should be solid before provider sync is added.
Create the Electron, React, TypeScript, Vite, linting, formatting, and test foundation.
Add SQLite migrations, repositories, local calendar defaults, and local event create/read/update/delete behavior.
Render local calendars and events with FullCalendar while keeping persistence in the local application service.
Persist event edits, drag/drop, resizing, and calendar visibility through the typed service API.
Store event reminders and add a main-process desktop notification foundation.
Support limited local recurrence storage and visible-range expansion.
Import and export local calendars through iCalendar .ics files.
Introduce provider-neutral adapters, sync state, outbox operations, and conflict policy using mock providers first.
Connect Google accounts securely, sync calendars/events, then add writable event operations.
Connect Outlook/Microsoft 365 accounts through Microsoft identity platform and sync through Microsoft Graph.
Add generic CalDAV account setup, discovery, and conservative event sync.
Add attendees, invite controls, free/busy, suggested times, and conference-link support where providers allow it.
Create documents/tasks with due dates and schedule linked calendar time blocks.
Add Windows/macOS packaging, signing/notarization notes, error handling, security review, QA checklists, and MVP reliability polish.