feat(VDatePicker): add events and event-color support for date picker

[maryamBaratii]

Description

• Restores the events and event-color props in VDatePicker for month view.
• Allows event markers to be displayed on months, similar to the behavior in Vuetify 2.
• Ensures the correct color is applied to event markers.
• Updated documentation to reflect the new props.

Fixes #19296

Markup:

<template>
  <v-app>
    <v-container>
      <v-date-picker
        :event-color="date => date[9] % 2 ? 'red' : 'yellow'"
        :events="functionEvents"
        :v-model="date2"
      />
    </v-container>
  </v-app>
</template>

<script setup>
  import { onMounted, ref } from 'vue'

  const arrayEvents = ref(null)
  const date2 = ref((new Date(Date.now() - (new Date()).getTimezoneOffset() * 60000)).toISOString().substr(0, 10))
  function functionEvents (date) {
    const [, , day] = date.split('-')
    if ([12, 17, 28].includes(parseInt(day, 10))) return true
    if ([1, 19, 22].includes(parseInt(day, 10))) return ['red', '#00f']
    return false
  }
  onMounted(() => {
    arrayEvents.value = [...Array(6)].map(() => {
      const day = Math.floor(Math.random() * 30)
      const d = new Date()
      d.setDate(day)
      return d.toISOString().substr(0, 10)
    })
  })
</script>

[maryamBaratii]

Hey @johnleider, I appreciate all the work you and the team do on Vuetify! I'd love to contribute to the project, and submitted this PR. I'd love to get your thoughts when you have time. Thanks!

[johnleider]

This is a .TSX file so you should be able to just return a function that returns an element.

[maryamBaratii]

Got it. I’ve updated the function to return an element directly. Let me know if any other changes are needed. Thanks!

[johnleider]

Hey @johnleider, I appreciate all the work you and the team do on Vuetify! I'd love to contribute to the project, and submitted this PR. I'd love to get your thoughts when you have time. Thanks!

I'll take a look. Is this mostly just copying what was there in V2? Also, since this is a feature, it will need to go to the dev branch.

Thank you!

[maryamBaratii]

Thanks, John! Yes, this restores the event and event-color props in VDatePicker, just like in Vuetify 2. Let me know if anything else needs tweaking.