Handling "legacy" proxy / proxy timeouts

[Art3miX]

Context discussion here

Account timeouts? I think the general idea is that once an account was created, it should stay "open" forever (same like creating a wallet), but we are talking about contracts here, and one simple question that pops to my mind is what happens if account isn't being used for lets say 5 years, and then we need to migrate from v1 to v50.
Proxy is a simple dispatcher contract and probably gonna stay that way, so this is probably fine, just feels like its important questions we should include in a doc so we won't forget about it in the future.

As said above, proxy accounts should stay open forever (much like wallets), but because proxy are contracts, there are extra factors we need to think about here.

I don't see any obvious way of knowing if an account is active or not, 1 account can stake some tokens in a contract for 5 years, and other account can just send tokens to pay for something, while the first one is active the second can be considered inactive.

1 factor of contracts to think about is migrations, what if a proxy is v1, but no one is used it for 5 years, and after 5 years we try to send a message on that proxy, but the updated proxy version now is v50, we know contract migrations are complex, and supporting migration from v1 to v50 seems to be unreasonable.

While #17 makes it clear that proxy migrations are gonna be minimal and not so complex as it has a simple dispatcher logic, we need to discuss and see if other contract factors might affect us here.