- Mail: Fix folder/account selector not triggering reload (use direct
fetch instead of reactive reload_needed flag)
- Tasks: Store all_projects/all_tags on mount so filters don't change
when filtering; add OR search for multiple tags
- Sync: Use rounded borders and border_title for sidebar/activity log
- Calendar: Remove padding from mini-calendar, add rounded border and
border_title to invites panel
- Create InvitesPanel widget showing pending invites from Microsoft Graph
- Add fetch_pending_invites() and respond_to_invite() API functions
- Invites load asynchronously in background on app mount
- Display invite subject, date/time, and organizer
- Add 'i' keybinding to focus invites panel
- Style: tentative invites shown in warning color
