Add Image Iterate: nested multi-prompt still families.

Iterate runs a series of prompts as generate (no still), edit (still A), or compose (A+B), saves each output under one library collection like video extensions, and defaults to iterating from the original still.

utils/libraryGeneration.ts

@@ -92,7 +92,7 @@ function stillDisplayLoraStack(settings: StillGenerationSettings) {
 export function normalizeStillSettings(raw: unknown): StillGenerationSettings | undefined {
   if (!raw || typeof raw !== 'object') return undefined
   const value = raw as Record<string, unknown>
-  const mode = value.mode === 'compose' || value.mode === 'refine' || value.mode === 'generate' || value.mode === 'edit'
+  const mode = value.mode === 'compose' || value.mode === 'refine' || value.mode === 'generate' || value.mode === 'edit' || value.mode === 'iterate'
     ? value.mode
     : undefined
   const engine = value.engine === 'krea' || value.engine === 'flux' ? value.engine : undefined
@@ -155,11 +155,13 @@ export function stillModeLabel(still: { filename?: string; settings?: StillGener
   if (settings?.kind === 'imagev2' || settings?.mode) {
     const mode = settings.mode === 'generate'
       ? 'Generate'
-      : settings.mode === 'compose'
-        ? 'Compose'
-        : settings.mode === 'refine'
-          ? 'Refine'
-          : 'Edit'
+      : settings.mode === 'iterate'
+        ? 'Iterate'
+        : settings.mode === 'compose'
+          ? 'Compose'
+          : settings.mode === 'refine'
+            ? 'Refine'
+            : 'Edit'
     const task = settings.mode === 'compose' ? composeTaskLabel(settings.task) : ''
     const engine = settings.engine === 'krea' ? 'Krea' : settings.engine === 'flux' ? 'Flux' : ''
     return [engine ? `Image v2 · ${mode} · ${engine}` : `Image v2 · ${mode}`, task].filter(Boolean).join(' · ')