Refactor date functions to use date fns date fns tz

[christianhelp]

Why

Currently, a lot of the date comparison logic inside of the event section is being done by functions we create instead of using the built-in libraries. Could lead to issue later on if not fixed.

What

Performed refactors and slight other enhancements to satisfy this

Satisfies

#80

[Copilot]

Copilot reviewed 13 out of 13 changed files in this pull request and generated 2 comments.

Comments suppressed due to low confidence (2)

apps/web/src/lib/queries/charts.ts:202

• Using a default value of 1 for currentMonthCount may artificially inflate the growth rate when there are no events in the current month; please verify that this logic reflects the intended behavior.

const currentMonthCount = currentMonthResult[0]?.count || 1;

apps/web/src/components/dash/admin/events/EditEventForm.tsx:133

• Consider adding eventEndTime to the dependency array for accurate re-evaluation of the condition when editing event times.

useEffect(() => {