I'm coming over to hang out tomorrow, okay?

Literal

Tomorrow play [purpose-に] go [so-から] [confirmation-ね].

からね at sentence-end combines explanatory から with confirmatory ね, creating a tone of 'I'm telling you this so you know' — advance notice rather than a request for permission. The speaker uses 行く (go) rather than 来る (come) because the destination is the listener's location, viewed from the speaker's current position.