refactor(plugins): expose bundled onboard helpers

extensions/mistral/api.ts

@@ -1,4 +1,14 @@
 export { buildMistralProvider } from "./provider-catalog.js";
+export {
+  buildMistralModelDefinition,
+  MISTRAL_BASE_URL,
+  MISTRAL_DEFAULT_MODEL_ID,
+} from "./model-definitions.js";
+export {
+  applyMistralConfig,
+  applyMistralProviderConfig,
+  MISTRAL_DEFAULT_MODEL_REF,
+} from "./onboard.js";
 
 const MISTRAL_MAX_TOKENS_FIELD = "max_tokens";