feat(baoyu-imagine): add OpenAI-compatible image API dialect support

Add --imageApiDialect flag, OPENAI_IMAGE_API_DIALECT env var, and
default_image_api_dialect config for gateways that expect aspect-ratio
size plus metadata.resolution instead of pixel size.

skills/baoyu-imagine/scripts/providers/openai.ts

@@ -1,6 +1,6 @@
 import path from "node:path";
 import { readFile } from "node:fs/promises";
-import type { CliArgs } from "../types";
+import type { CliArgs, OpenAIImageApiDialect } from "../types";
 
 export function getDefaultModel(): string {
   return process.env.OPENAI_IMAGE_MODEL || "gpt-image-1.5";
@@ -23,6 +23,8 @@ type SizeMapping = {
   portrait: string;
 };
 
+type OpenAIGenerationsBody = Record<string, unknown>;
+
 export function getOpenAISize(
   model: string,
   ar: string | null,
@@ -60,6 +62,114 @@ export function getOpenAISize(
   return sizes.square;
 }
 
+function parsePixelSize(value: string): { width: number; height: number } | null {
+  const match = value.match(/^(\d+)\s*[xX]\s*(\d+)$/);
+  if (!match) return null;
+
+  const width = parseInt(match[1]!, 10);
+  const height = parseInt(match[2]!, 10);
+  if (!Number.isFinite(width) || !Number.isFinite(height) || width <= 0 || height <= 0) {
+    return null;
+  }
+
+  return { width, height };
+}
+
+function gcd(a: number, b: number): number {
+  let x = Math.abs(a);
+  let y = Math.abs(b);
+  while (y !== 0) {
+    const next = x % y;
+    x = y;
+    y = next;
+  }
+  return x || 1;
+}
+
+export function getOpenAIImageApiDialect(args: Pick<CliArgs, "imageApiDialect">): OpenAIImageApiDialect {
+  return args.imageApiDialect ?? "openai-native";
+}
+
+export function inferAspectRatioFromSize(size: string | null): string | null {
+  if (!size) return null;
+  const parsed = parsePixelSize(size);
+  if (!parsed) return null;
+
+  const divisor = gcd(parsed.width, parsed.height);
+  return `${parsed.width / divisor}:${parsed.height / divisor}`;
+}
+
+export function inferResolutionFromSize(size: string | null): "1K" | "2K" | "4K" | null {
+  if (!size) return null;
+  const parsed = parsePixelSize(size);
+  if (!parsed) return null;
+
+  const longestEdge = Math.max(parsed.width, parsed.height);
+  if (longestEdge <= 1024) return "1K";
+  if (longestEdge <= 2048) return "2K";
+  return "4K";
+}
+
+export function getOpenAIAspectRatio(args: Pick<CliArgs, "aspectRatio" | "size">): string {
+  return args.aspectRatio ?? inferAspectRatioFromSize(args.size) ?? "1:1";
+}
+
+export function getOpenAIResolution(
+  args: Pick<CliArgs, "imageSize" | "size" | "quality">
+): "1K" | "2K" | "4K" {
+  if (args.imageSize === "1K" || args.imageSize === "2K" || args.imageSize === "4K") {
+    return args.imageSize;
+  }
+
+  const inferred = inferResolutionFromSize(args.size);
+  if (inferred) return inferred;
+
+  return args.quality === "normal" ? "1K" : "2K";
+}
+
+export function getOrientationFromAspectRatio(ar: string): "landscape" | "portrait" | null {
+  const parsed = parseAspectRatio(ar);
+  if (!parsed) return null;
+
+  const ratio = parsed.width / parsed.height;
+  if (Math.abs(ratio - 1) < 0.1) return null;
+  return ratio > 1 ? "landscape" : "portrait";
+}
+
+export function buildOpenAIGenerationsBody(
+  prompt: string,
+  model: string,
+  args: Pick<CliArgs, "aspectRatio" | "size" | "quality" | "imageSize" | "imageApiDialect">
+): OpenAIGenerationsBody {
+  if (getOpenAIImageApiDialect(args) === "ratio-metadata") {
+    const aspectRatio = getOpenAIAspectRatio(args);
+    const metadata: Record<string, string> = {
+      resolution: getOpenAIResolution(args),
+    };
+    const orientation = getOrientationFromAspectRatio(aspectRatio);
+    if (orientation) metadata.orientation = orientation;
+
+    return {
+      model,
+      prompt,
+      size: aspectRatio,
+      metadata,
+    };
+  }
+
+  const body: OpenAIGenerationsBody = {
+    model,
+    prompt,
+    size: args.size || getOpenAISize(model, args.aspectRatio, args.quality),
+  };
+
+  if (model.includes("dall-e-3")) {
+    body.quality = args.quality === "2k" ? "hd" : "standard";
+  }
+
+  return body;
+}
+
 export async function generateImage(
   prompt: string,
   model: string,
@@ -78,18 +188,28 @@ export async function generateImage(
     return generateWithChatCompletions(baseURL, apiKey, prompt, model);
   }
 
-  const size = args.size || getOpenAISize(model, args.aspectRatio, args.quality);
+  const imageApiDialect = getOpenAIImageApiDialect(args);
 
   if (args.referenceImages.length > 0) {
+    if (imageApiDialect !== "openai-native") {
+      throw new Error(
+        "Reference images are not supported with the ratio-metadata OpenAI dialect yet. Use openai-native, Google, Azure, OpenRouter, MiniMax, Seedream, or Replicate for image-edit workflows."
+      );
+    }
     if (model.includes("dall-e-2") || model.includes("dall-e-3")) {
       throw new Error(
         "Reference images with OpenAI in this skill require GPT Image models. Use --model gpt-image-1.5 (or another gpt-image model)."
       );
     }
+    const size = args.size || getOpenAISize(model, args.aspectRatio, args.quality);
     return generateWithOpenAIEdits(baseURL, apiKey, prompt, model, size, args.referenceImages, args.quality);
   }
 
-  return generateWithOpenAIGenerations(baseURL, apiKey, prompt, model, size, args.quality);
+  return generateWithOpenAIGenerations(
+    baseURL,
+    apiKey,
+    buildOpenAIGenerationsBody(prompt, model, args)
+  );
 }
 
 async function generateWithChatCompletions(
@@ -129,17 +249,8 @@ async function generateWithChatCompletions(
 async function generateWithOpenAIGenerations(
   baseURL: string,
   apiKey: string,
-  prompt: string,
-  model: string,
-  size: string,
-  quality: CliArgs["quality"]
+  body: OpenAIGenerationsBody
 ): Promise<Uint8Array> {
-  const body: Record<string, any> = { model, prompt, size };
-
-  if (model.includes("dall-e-3")) {
-    body.quality = quality === "2k" ? "hd" : "standard";
-  }
-
   const res = await fetch(`${baseURL}/images/generations`, {
     method: "POST",
     headers: {