feat(ci): enable go test in CI pipeline (#15750)

## What problem does this PR solve?

Go test files are never compiled in CI — only production binaries via
`go build`. This allowed a missing `"sort"` import in
`metadata_filter_test.go` to be merged without detection.

## Type of change

- [x] Bug Fix (non-breaking change which fixes an issue)
- [x] New Feature (non-breaking change which adds functionality)

## Changes

- Add `go test -count=1 ./internal/...` step after Go build in CI
workflow
- Fix missing `"sort"` import in `metadata_filter_test.go` (pre-existing
compile error)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

---------

Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>

internal/entity/models/replicate_test.go

@@ -309,10 +309,14 @@ func TestReplicateListModelsAndCheckConnection(t *testing.T) {
 
 func TestReplicateUnsupportedMethods(t *testing.T) {
 	m := newReplicateForTest("http://unused")
-	if _, err := m.Rerank(nil, "", nil, nil, nil); err == nil || !strings.Contains(err.Error(), "no such method") {
+	apiKey := "test-key"
+	// Rerank IS implemented; with empty documents it short-circuits (no error).
+	// Pass non-empty docs + nil modelName to trigger model-name validation.
+	if _, err := m.Rerank(nil, "", []string{"d"}, &APIConfig{ApiKey: &apiKey}, nil); err == nil || !strings.Contains(err.Error(), "model name is required") {
 		t.Errorf("Rerank error=%v", err)
 	}
-	if _, err := m.Balance(nil); err == nil || !strings.Contains(err.Error(), "no such method") {
+	// Balance IS a stub → "no such method"
+	if _, err := m.Balance(&APIConfig{ApiKey: &apiKey}); err == nil || !strings.Contains(err.Error(), "no such method") {
 		t.Errorf("Balance error=%v", err)
 	}
 }