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Build me a calendar client over CalDAV with a parser that turns a sentence into an event.

STACK
- Tauri or a native app; CalDAV for every account, no proprietary backend
- SQLite as a local cache, rebuildable from the server

THE PARSER, WHICH IS THE PRODUCT
- "Lunch with Ana thursday 1pm at Nero for an hour, alert 15 min before" must produce the right event
- Grammar order: title, then people, then date and time, then location, then duration, then alerts
- Show the parsed event as a card before it is created; never create from an ambiguous parse

RECURRENCE
- Support RRULE properly: weekly by day, monthly by ordinal weekday, and an exception list
- A recurring event edited once creates an exception, not a new series, and the interface says which is happening

TIMEZONES
- Every event stored in UTC with its original zone kept
- An event created while travelling keeps the zone it was created for, and the README explains the difference

SYNC
- CalDAV with ETags; a changed event that fails the ETag check is refetched, never blindly overwritten
- Offline changes queued and replayed in order

INVITATIONS
- Read attendee status; send replies as iTIP messages over the account's mail

Include a README on the parser grammar, the RRULE subset supported, and the ETag conflict path.