fix: normalize path separators in Go crawler PURLs on Windows

On Windows, `Path::strip_prefix` + `to_string_lossy()` produces
backslashes in the relative path, which get embedded in the PURL
(e.g., `pkg:golang/github.com\\gin-gonic\\gin@v1.9.1`). Replace
backslashes with forward slashes to produce correct PURLs on all
platforms.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: mikolalysenko

crates/socket-patch-core/src/crawlers/go_crawler.rs

@@ -276,9 +276,10 @@ impl GoCrawler {
         _dir_name: &str,
         seen: &mut HashSet<String>,
     ) -> Option<CrawledPackage> {
-        // Get the relative path from the cache root
+        // Get the relative path from the cache root.
+        // Normalize to forward slashes so PURLs are correct on Windows.
         let rel_path = dir_path.strip_prefix(base_path).ok()?;
-        let rel_str = rel_path.to_string_lossy();
+        let rel_str = rel_path.to_string_lossy().replace('\\', "/");
 
         // Find the last `@` to split module path and version
         let at_idx = rel_str.rfind('@')?;