Centralize output schema and module key validation catalogs

internal/core/modulecatalog/catalog.go

@@ -0,0 +1,35 @@
+package modulecatalog
+
+import "strings"
+
+const (
+	KeyGlossary   = "glossary"
+	KeyHomophones = "homophones"
+	KeySpokenWord = "spoken_word"
+	KeyGrammar    = "grammar"
+)
+
+var supportedKeys = []string{
+	KeyGlossary,
+	KeyHomophones,
+	KeySpokenWord,
+	KeyGrammar,
+}
+
+var supportedKeySet = map[string]struct{}{
+	KeyGlossary:   {},
+	KeyHomophones: {},
+	KeySpokenWord: {},
+	KeyGrammar:    {},
+}
+
+func SupportedKeys() []string {
+	out := make([]string, len(supportedKeys))
+	copy(out, supportedKeys)
+	return out
+}
+
+func IsSupported(key string) bool {
+	_, ok := supportedKeySet[strings.TrimSpace(key)]
+	return ok
+}