Document copyRecord guarantees

[erights]

@jessysaurusrex I'm including you, because my intention is that, once we follow the advice on this page, that this page is helpful for reviewers auditing code using this kind of input validation.

In a peculiar way, this is a start on a semantics of our distributed object system. But it is inside out precisely to focus on the meaning of these checks as input validation.

[michaelfig]

Good stuff. It really needs a compelling name, though, so I'll not go so far as to approve, but won't block other approvals.

[katelynsills]

This looks good to me! One question: should this explanation also explain what a Structure is, and how to assert that? Amounts must be Structures (no promises). Maybe just a sentence explanation and link to information on structures?

[erights]

This looks good to me! One question: should this explanation also explain what a Structure is, and how to assert that? Amounts must be Structures (no promises). Maybe just a sentence explanation and link to information on structures?

This part is about to change again. I'll wait until it settles down.