refactor: optimize code with modern Go patterns and pre-allocation (#3576)

This commit modernizes code across multiple packages by:
- Using Go 1.18+ features (slices.IndexFunc, strings.Cut)
- Pre-allocating slices and maps with known capacity
- Consolidating defensive checks and improving code clarity
- Fixing test data and build tag issues

CLI client improvements:
- Pre-allocate slices in search functions and service methods
- Replace strings.Split with strings.Cut for username:password parsing
- Use range-based iteration instead of manual index loops

Search extension optimizations:
- Cache sort functions in pagination modules
- Pre-allocate page buffers and maps
- Consolidate defensive checks in filterBaseImages/filterDerivedImages
- Fix image bas and derived logic allowing out of sequence layers for base images
- Fix image pagination reporting images groupped by repos when sorted by update time
- Remove duplicate resolver_test.go file

Monitoring extension:
- Replace manual loops with slices.IndexFunc
- Pre-allocate bucketsFloat2String map

Sync extension:
- Pre-allocate slice in parseRegistryURLs

Test utilities:
- Fix build tags in oci_layout.go

Signed-off-by: Andrei Aaron <andreifdaaron@gmail.com>

pkg/extensions/sync/utils.go

@@ -46,7 +46,7 @@ func parseReference(reference string) (digest.Digest, bool) {
 
 // Given a list of registry string URLs parse them and return *url.URLs slice.
 func parseRegistryURLs(rawURLs []string) ([]*url.URL, error) {
-	urls := make([]*url.URL, 0)
+	urls := make([]*url.URL, 0, len(rawURLs))
 
 	for _, rawURL := range rawURLs {
 		u, err := url.Parse(rawURL)