fix(storage): normalize repository names to '/' separators on Windows (#4188)

filepath.Rel returns OS-specific separators, so on Windows the repo
walkers (GetRepositories, GetNextRepository, GetNextRepositories)
produced backslash-separated names such as 'openshift4\ose-cli'. Those
names fail FullNameRegexp validation in ValidateRepo, which only
accepts '/' as a component separator, so every namespaced repository
was silently dropped. As a result /v2/_catalog returned an empty list,
and garbage collection, scrub, and metadb never saw any repositories.

Convert each relative path with filepath.ToSlash (a no-op on Unix)
before validation, matching the existing ToSlash usage elsewhere in
imagestore.go.

Signed-off-by: zaldre <zaldre@zaldre.com>
Co-authored-by: zaldre <zaldre@zaldre.com>

Author: zaldre

pkg/storage/imagestore/imagestore.go

@@ -310,6 +310,8 @@ func (is *ImageStore) GetNextRepositories(lastRepo string, maxEntries int, filte
 			return nil //nolint:nilerr // ignore paths that are not under root dir
 		}
 
+		rel = filepath.ToSlash(rel)
+
 		if ok, err := is.ValidateRepo(rel); !ok || err != nil {
 			return nil //nolint:nilerr // ignore invalid repos
 		}
@@ -384,6 +386,8 @@ func (is *ImageStore) GetRepositories() ([]string, error) {
 			return nil //nolint:nilerr // ignore paths that are not under root dir
 		}
 
+		rel = filepath.ToSlash(rel)
+
 		if ok, err := is.ValidateRepo(rel); !ok || err != nil {
 			return nil //nolint:nilerr // ignore invalid repos
 		}
@@ -435,6 +439,8 @@ func (is *ImageStore) GetNextRepository(processedRepos map[string]struct{}) (str
 			return nil //nolint:nilerr // ignore paths not relative to root dir
 		}
 
+		rel = filepath.ToSlash(rel)
+
 		if _, ok := processedRepos[rel]; ok {
 			return nil // repo already processed
 		}