King Achashverosh, the high priest?

Masechet Megillah's surprising comment on the King in Shushan.

In this week’s Torah portion, Tetzaveh, we read this instruction to Moses on the clothing Aaron, the high priest, will wear:

וְעָשִׂ֥יתָ בִגְדֵי־קֹ֖דֶשׁ לְאַהֲרֹ֣ן אָחִ֑יךָ לְכָב֖וֹד וּלְתִפְאָֽרֶת׃
Make sacred vestments for your brother Aaron, for dignity (kavod) and adornment (tiferet). (Exodus 28:2)

This verse seems relatively simple on its surface. Sfo…