Does the halting problem imply any limits on human cognition?
Yes, absolutely--that there are pieces of code a human could look at and not be sure whether or not it will halt in finite time. (Certainly there are pieces of code that a human can look at and say "yes" or "no" definitely, but we're talking about the ones that are actually quite difficult to analyze.)
The halting problem means that there are types of code analysis that no computer could do, because it's mathematically impossible. But the realm of possibility is still large enough to allow strong artificial intelligence (in the sense of code that can understand itself well enough to improve itself).