refactor(date): delegate to v0 createDate as runtime

[johnleider]

Summary

• Migrate Vuetify's date system to use @vuetify/v0's createDate() as the runtime
• Replace VuetifyDateAdapter (native Date) with v0's Vuetify0DateAdapter (Temporal)
• Add VuetifyDateBridge<T> to translate Vuetify's string|number param types to v0's number
• Add LegacyDateAdapterCompat<T> for backwards compat with old custom adapters
• Rewrite StringDateAdapter over v0's Temporal adapter
• Consolidate two injection symbols (DateOptionsSymbol + DateAdapterSymbol) into single DateSymbol
• Update framework.ts to use date.install(app) pattern

Closes vuetifyjs/0#111

Breaking Changes

• Default date type shifts from Date to Temporal.PlainDateTime
• Custom adapter authors must implement v0's DateAdapter<T> interface (compat shim provided with deprecation warning)
• DateAdapterSymbol deprecated — use useDate() instead
• Third-party date lib adapters will come from @vuetify/v0 (once shipped)

[J-Sek]

if v0 is not meant to accept firstDayOfWeek, the workaround would be:

withWeekInfoOverride<T> (action: () => T, firstDayOfWeek?: number): T {
  const old = this.base.firstDayOfWeek
  this.base.firstDayOfWeek = firstDayOfWeek ?? this.base.firstDayOfWeek
  const result = action()
  this.base.firstDayOfWeek = old
  return result
}

startOfWeek (date: string, firstDayOfWeek?: number): string {
  const action = () => this.fromBase(this.base.startOfWeek(this.toBase(date)))
  return firstDayOfWeek
    ? this.withWeekInfoOverride(action, firstDayOfWeek)
    : action()
}

endOfWeek (date: string, firstDayOfWeek?: number): string {
  const action = () => this.fromBase(this.base.endOfWeek(this.toBase(date)))
  return this.withWeekInfoOverride(action, firstDayOfWeek) // shorter if it matters
}

// repeat for:
// - getWeek
// - getWeekdays
// - getWeekArray