test(05-03): add failing tests for VerifyAll worker pool

- TestVerifyAll_MultipleFindings: 5 findings via 3-worker pool
- TestVerifyAll_MissingProvider: unknown provider yields StatusUnknown
- TestVerifyAll_ContextCancellation: cancellation closes channel early
- Add providers.NewRegistryFromProviders test helper

pkg/providers/registry.go

@@ -39,6 +39,21 @@ func NewRegistry() (*Registry, error) {
 	}, nil
 }
 
+// NewRegistryFromProviders builds a Registry from an explicit slice of providers
+// without touching the embedded YAML files. Intended for tests that need a
+// minimal registry with synthetic providers.
+func NewRegistryFromProviders(ps []Provider) *Registry {
+	index := make(map[string]int, len(ps))
+	var keywords []string
+	for i, p := range ps {
+		index[p.Name] = i
+		keywords = append(keywords, p.Keywords...)
+	}
+	builder := ahocorasick.NewAhoCorasickBuilder(ahocorasick.Opts{DFA: true})
+	ac := builder.Build(keywords)
+	return &Registry{providers: ps, index: index, ac: ac}
+}
+
 // List returns all loaded providers.
 func (r *Registry) List() []Provider {
 	return r.providers