The Chinese rules state that you cannot repeat a board position (where "position" includes whose move it is). The Japanese rules only rule out the shortest form of repition, and other pathological situations like triple ko lead to the game being withdrawn (as I understand it, it is not "drawn", it is simply considered not to have been played).
The rule that you cannot immediately return to a previous state (i.e., a simple ko) handles the vast majority of situations that actually occur (so many that it is probably not worth coding anything more elaborate).
Suicide is illegal in go (don't know about gonnect). A mathematician friend (and 6 dan) has argued to me that it would be more elegant to allow suicide in some situations as a ko threat, but rules are rules.
PS The server can't be expected to score a go game since that depends on which groups are alive. If you had a program that could decide that without fail, you'd have the basis for a really strong player.