feat: adapt image tuning by engine

lib/server/generation-service.ts

@@ -42,6 +42,7 @@ export type SubmitImageJobInput = {
   max_ratio?: number;
   force_single?: boolean;
   resolution?: "4k" | "8k";
+  quality?: string;
   seed?: number;
   retryOf?: string;
   idempotencyKey?: string;

lib/server/public-api-jobs.ts

@@ -35,6 +35,7 @@ export type PublicJobCreateBody = {
   max_ratio?: number;
   force_single?: boolean;
   resolution?: "4k" | "8k";
+  quality?: string;
   seed?: number;
 };
 
@@ -101,6 +102,7 @@ export async function createPublicGenerationJob(input: {
     max_ratio: asNumber(input.body.max_ratio),
     force_single: Boolean(input.body.force_single),
     resolution: input.body.resolution,
+    quality: normalizeQuality(input.body.quality),
     seed: asNumber(input.body.seed)
   } satisfies SubmitImageJobInput, input.origin);
   return { job, reused: false };
@@ -132,6 +134,12 @@ function asNumber(value: unknown): number | undefined {
   return Number.isFinite(parsed) ? parsed : undefined;
 }
 
+function normalizeQuality(value: unknown): string | undefined {
+  if (typeof value !== "string") return undefined;
+  const normalized = value.trim().toLowerCase();
+  return ["low", "medium", "high"].includes(normalized) ? normalized : undefined;
+}
+
 function fingerprintBody(body: PublicJobCreateBody): string {
   const { idempotencyKey: _idempotencyKey, ...fingerprintSource } = body;
   return createHash("sha256").update(stableStringify(fingerprintSource)).digest("hex");