eazip: symlink-target validation checks the wrong argument, allowing extraction path escapes on Windows

When extracting archives, `eazip` validates symlink entries before writing
them. The validation function `validate_symlink()` (`src/utils/mod.rs`) scans
for backslash and NUL bytes, but passes the symlink's *name* where the
symlink's *target* was intended:

```rust
memchr2(b'\\', b'\0', name.as_bytes()) // should be target.as_bytes()
```

As a result, symlink *targets* containing backslash or NUL bytes pass
validation. On Windows, backslash is a path separator, so targets such as
`..\..\..\Windows\system32\evil.exe` also defeat the remaining depth check,
which splits on `/` only. A crafted archive can therefore create symlinks
that resolve outside the extraction directory — including UNC targets such as
`\\host\share\...` — redirecting writes to arbitrary filesystem locations
chosen by the attacker.

Applications that extract untrusted archives with `eazip` on Windows targets
are affected; on Unix targets backslash is not a separator, which limits
exposure there.

The vulnerability was introduced in version 0.2.5 and fixed in 0.2.7
([a1phyr/eazip@0e4caa13](https://github.com/a1phyr/eazip/commit/0e4caa13d59f5ba15aaac332f5534260c3b8fc43)),
which rejects backslash and NUL bytes in the symlink target. It was
privately reported to the maintainer on 2026-11-06 and credited in the
0.2.7 release notes.