fix: adapt ruxa nano banana 2 runtime

lib/ai/providers/ruxa-image.ts

@@ -24,6 +24,21 @@ const DEFAULT_RESOLUTION = "1k";
 const DEFAULT_OUTPUT_FORMAT = "png";
 const POLL_INTERVAL_MS = 2000;
 const POLL_MAX_ATTEMPTS = 90;
+const RUXA_NANO_BANANA_2_DOC_MODEL_ID = "gemini-3.1-flash-image-preview";
+const RUXA_MODEL_ID_ALIASES: Record<string, string> = {
+  "google/nano-banana-2": RUXA_NANO_BANANA_2_DOC_MODEL_ID,
+};
+
+function normalizeRuxaModelId(modelId?: string) {
+  const raw = String(modelId || "").trim();
+  if (!raw) return "gpt-image-1.5";
+  return RUXA_MODEL_ID_ALIASES[raw] || raw;
+}
+
+function isRuxaNanoBanana2Model(modelId?: string) {
+  const normalized = normalizeRuxaModelId(modelId);
+  return normalized === RUXA_NANO_BANANA_2_DOC_MODEL_ID;
+}
 
 function normalizeUrlForCompare(url: string) {
   try {
@@ -74,6 +89,14 @@ function normalizeOutputFormat(outputFormat?: string): "png" | "jpg" | "webp" {
   return "png";
 }
 
+function normalizeRuxaOutputFormat(modelId: string | undefined, outputFormat?: string) {
+  const normalized = normalizeOutputFormat(outputFormat);
+  if (!isRuxaNanoBanana2Model(modelId)) {
+    return normalized;
+  }
+  return normalized === "jpg" ? "jpeg" : normalized;
+}
+
 function extractTaskId(payload: any): string | undefined {
   if (typeof payload === "string" && payload.trim()) {
     return payload.trim();
@@ -370,17 +393,23 @@ export function createRuxaImage({ apiKey, baseURL }: RuxaImageConfig) {
         const { prompt, imageUrls } = extractPromptAndImages(options.messages);
         const aspectRatio = normalizeAspectRatio(options.imageParams?.aspectRatio);
         const resolution = normalizeResolution(options.imageParams?.imageSize);
-        const outputFormat = normalizeOutputFormat(options.imageParams?.outputFormat);
+        const requestedModelId = options.overrideModelId || modelId || "gpt-image-1.5";
-        const activeModelId = options.overrideModelId || modelId || "gpt-image-1.5";
+        const activeModelId = normalizeRuxaModelId(requestedModelId);
+        const outputFormat = normalizeRuxaOutputFormat(activeModelId, options.imageParams?.outputFormat);
+        const isNanoBanana2 = isRuxaNanoBanana2Model(activeModelId);
 
         const createEndpoint = joinApiPath(baseURL, "/api/v1/tasks/create");
         const callbackUrl = process.env.RUXA_CALLBACK_URL?.trim();
         const input: Record<string, unknown> = {
           prompt,
-          resolution,
           output_format: outputFormat,
         };
-        if (aspectRatio) {
+        if (isNanoBanana2) {
+          input.size = aspectRatio || "1:1";
+        } else {
+          input.resolution = resolution;
+        }
+        if (aspectRatio && !isNanoBanana2) {
           input.size = aspectRatio;
           input.aspect_ratio = aspectRatio;
         }
@@ -395,6 +424,12 @@ export function createRuxaImage({ apiKey, baseURL }: RuxaImageConfig) {
           model: activeModelId,
           ...(callbackUrl ? { callBackUrl: callbackUrl } : {}),
         };
+        if (activeModelId !== requestedModelId) {
+          console.log("[Ruxa Image] Remapped modelId for provider compatibility:", {
+            requestedModelId,
+            activeModelId,
+          });
+        }
         const createResponse = await fetch(createEndpoint, {
           method: "POST",
           headers: {