try to fix date key equality issue

[joshuaslate]

I'm trying to fix the following error from TransitionInTx:

rpc error: code = FailedPrecondition desc = event key date value year:2025 month:6 day:26 does not match existing value year:2025 month:6 day:26

I thought to maybe make an interface that the key types could implement, something like:

type Comparable interface {
  Equals(other any) bool
}

So something like:

PSMKeyValues() (map[string]Comparable, error)

Instead of:

PSMKeyValues() (map[string]any, error)

[joshuaslate]

This fixed my issue. Dan told me I should go ahead and merge.