What is $0^{i}$?

This was a comment, but @hjhjhj57 suggested that it might serve as an answer.

If you write the right-hand side of your equation as $\lim_{t\to−∞}e^{it}=\lim_{t\to−∞}(e^i)^t$, it’s completely clear that the limit doesn’t exist: you’re taking the number $e^i$, which is on the unit circle, and raising it to a large (but negative) power. You have a point that runs around the unit circle infinitely many times as $t\to−∞$, no limit at all.

It is possible to interpret such expressions in many ways that can make sense. The question is, what properties do we want such an interpretation to have?

$0^i = 0$ is a good choice, and maybe the only choice that makes concrete sense, since it follows the convention $0^x = 0$. On the other hand, $0^{-1} = 0$ is clearly false (well, almost—see the discussion on goblin's answer), and $0^0=0$ is questionable, so this convention could be unwise when $x$ is not a positive real.

Digging deeper: One generally defines complex exponentiation as a multi-valued function: if $e^c = a$, then we can define $a^x = e^{cx}$. This is not unique, since it depends on the choice of $c$, but it's a good way to think about quantities like $i^i$ (this is sometimes claimed to be $e^{-\pi/2}$, but it can be interpreted as $e^{-\pi/2 + 2\pi n}$ for any $n\in\mathbb{Z}$)

This approach breaks down for $0^i$, because $0$ has no natural logarithm in the complex numbers. However, if we're comfortable calling $-\infty$ (or $-\infty + 2\pi i n$) a natural log of $0$, then we can say that $0^x = e^{-\infty \cdot x} = 0$ when $x$ has positive real part.

When $x$ has negative real part, this leads us to regard $0^x$ as a quantity with infinite magnitude and undefined argument. When $x$ is imaginary, the argument is still undefined, but the magnitude is multi-valued rather than infinite.

My conclusion is that we should avoid assigning meaning to $0^i$.

Writing $|0^i| = 1$ may be sensible, however, under some circumstances.

In a general setting, I would be comfortable saying that $|0^i| = e^{2\pi n}$, for any $n\in\mathbb{Z}$.