Timeweight all boardroom staked MIS during seigniorage distribution

Current state: Currently, full pro-rata epoch is provided to all MIS boardroom stakers, no matter when your MIS is staked

Issue: Incentivizes people to maintain optionality by keeping MIS on the sidelines, doesn't reward long term support for community

Proposal: Timeweight all boardroom staked MIS, to reflect "total staked MIS by community", "your staked MIS", "your effective staked MIS", "potential reward this epoch. This way, community is rewarded for longer term support. Longer you stake your MIS in the 24 hours prior, the more your staked MIS is worth (pro-rata to time staked), the more of epoch you get

Expected Result: People will lock their MIS in the boardroom, feel significant pinch about taking out MIS / putting back in, and think hard before taking out of boardroom for whatsoever reason

Potential issue: Lack of liquidity of MIS outside of boardroom

+++++

For: Timeweight all boardroom staked MIS per proposal above

Against: Do nothing