[ty] Detect recursive alias cycles through intersections (#28916)
## Summary
We now report `cyclic-type-alias-definition` instead of overflowing the
stack for PEP 613 aliases such as:
```python
from typing import TypeAlias
A: TypeAlias = "~A & A"
```
Cycle detection now follows both positive and negative intersection
elements, so intersections and negations cannot hide unguarded recursive
references. This also covers mutual recursion and PEP 695 aliases, while
recursion through a containing type remains valid.
Closes https://github.com/astral-sh/ty/issues/4601.
