Check again, after the finish line the safety car is struck from behind
Overlap is exactly what it says it is, overlap between two side by side cars. Every series has it's own rules on what is considered sufficient overlap.
Most series define overlap as the front of the inside car being level with the drivers head of the outside car. From that point onwards the inside car is deemed to have 'sufficient overlap' for the move, from behind that point the outside car is deemed to have the line.
I do not know the rules of this event as I was not part of it, and I only saw your accident on the last 10 lap you tube video, so i'm ill equipped to judge - from a spectators perspective it looks like you got your nose on the inside of the rear wheels of the car ahead. In most series that would not be sufficient overlap, and a move which whilst watching I put down to driver inexperience of the chasing [your] car.
If the rules of the event say otherwise regarding the move, then that's all fair, in the rules of most series however as a steward i'd just leave that one without feeling the need to apply any penalty.
No other factor of strategy or intent is rellevent, a move is judged just on the move itself: Did the inside car have sufficient overlap to have the corner; or did the outside car have right of way.
Just to clarify an unclear point from your posts, the most common is to get the front of the car in line with the drivers head on the grounds that this is the extent of peripheral vision (in RL anyway). Getting your nose infront of the rear wheels isnt sufficient overlap in most series and the outside car is perfectly entitled to slam the door shut on you. What's most common in oval racing however I do not know.