Add `gadget:TeamResourceExcess(teamID, metal, energy) -> bool handled`

Add a Lua event that lets a game handle resource excess. This would be anytime it goes to `resDelayedShare` in the current implementation. If a game doesn't handle it, direct it to `resDelayedShare` same as current.

Locate the current implementation's resDelayedShare path and trace when resource excess is detected. Review the Lua event API around that entry point, then verify that TeamResourceExcess(teamID, metal, energy) can handle the case and that unhandled cases still follow the existing resDelayedShare behavior.

Written by the indexing model from the issue text.