[tyler-dane]

What and why

Brings native week grid event jump in line with web (#4723) on top of #4710:

• Lowercase chip labels (su1, f4, …), not uppercase
• Unified DayJumpKeys.matchKeystroke for day letters, weekend s→u/a, and digit sequences (f4, su8)
• Uppercase input accepted as alias
• Bare f while jump mode is active selects Friday (does not toggle jump off); first f still activates jump via focusShiftHold
• Esc still clears jump mode

Reuses keystroke/test patterns from cursor/macos-event-jump-lowercase-ddc9 (6084961), adapted to main’s DayJumpKeys API.

Verify

VERDICT: PASS
Selected packages: macos
Checks run: type-check, lint, knip

Swift unit + XCUITest: DayJumpKeysTests, NativeCalendarRootModelEventJumpTests, EventJumpDayPrefixUITests.