[ty] Full-scope bidirectional inference for non-empty collection literals (#25280)
Extends https://github.com/astral-sh/ruff/pull/25279 to support
full-scope inference for all unannotated collection literals, even those
that are non-empty, e.g.,
```py
x = [1]
x.append("2")
reveal_type(x) # revealed: list[int | str]
```