Update editor generation pricing defaults

Unify and lower default mud-point prices across editor generation features and update related API/schema, docs and tests. Changes set gpt-image-2 to 1K=3 / 2K=5, audio1.0 to 5, and chirp-v5 to 12, and update server default JSON, frontend models/workflows, OpenAPI schema (require aspectRatio/imageSize/priceMudPoints for UI extraction), multiple UX docs (quick-edit viewport, UI extraction panel, pricing guidance) and accompanying tests to match the new defaults and validation rules.

src/components/image-editor/ImageCanvasUiAssetExtractionModel.ts

@@ -26,25 +26,48 @@ export type UiAssetExtractionMark =
 
 export type UiAssetExtractionState = {
   sourceLayerId: string;
-  tool: UiAssetExtractionTool;
+  tool: UiAssetExtractionTool | null;
   marks: UiAssetExtractionMark[];
   draftMark: UiAssetExtractionMark | null;
   status: 'idle' | 'extracting' | 'failed';
   errorMessage?: string;
 };
 
+export const UI_ASSET_EXTRACTION_ASPECT_RATIO = '1:1';
+export const UI_ASSET_EXTRACTION_SMALL_IMAGE_SIZE = '1K';
+export const UI_ASSET_EXTRACTION_LARGE_IMAGE_SIZE = '2K';
+export const UI_ASSET_EXTRACTION_LARGE_SIZE_MARK_THRESHOLD = 6;
+
+export type UiAssetExtractionImageSize =
+  | typeof UI_ASSET_EXTRACTION_SMALL_IMAGE_SIZE
+  | typeof UI_ASSET_EXTRACTION_LARGE_IMAGE_SIZE;
+
 export function createUiAssetExtractionState(
   sourceLayerId: string,
+  options: { initialTool?: UiAssetExtractionTool | null } = {},
 ): UiAssetExtractionState {
   return {
     sourceLayerId,
-    tool: 'rect',
+    tool: options.initialTool === undefined ? 'rect' : options.initialTool,
     marks: [],
     draftMark: null,
     status: 'idle',
   };
 }
 
+export function resolveUiAssetExtractionGenerationPlan(markCount: number): {
+  aspectRatio: typeof UI_ASSET_EXTRACTION_ASPECT_RATIO;
+  imageSize: UiAssetExtractionImageSize;
+} {
+  return {
+    aspectRatio: UI_ASSET_EXTRACTION_ASPECT_RATIO,
+    imageSize:
+      markCount > UI_ASSET_EXTRACTION_LARGE_SIZE_MARK_THRESHOLD
+        ? UI_ASSET_EXTRACTION_LARGE_IMAGE_SIZE
+        : UI_ASSET_EXTRACTION_SMALL_IMAGE_SIZE,
+  };
+}
+
 export function createUiAssetExtractionDraftMark({
   tool,
   id,