Add extension-frame refine and lossless anchor options.

Prefer clip anchor PNGs for handoffs, optionally run Bilateral+Flux cleanup before I2V, and save decoded last-frame anchors so sequential extensions accumulate less compression damage.

Co-authored-by: Cursor <cursoragent@cursor.com>

utils/extensionFrame.ts

@@ -0,0 +1,22 @@
+export const REFINEMENT_DENOISE_MIN = 0.1
+export const REFINEMENT_DENOISE_MAX = 0.25
+export const REFINEMENT_DENOISE_DEFAULT = 0.18
+
+export function clampRefinementDenoise(raw: unknown, fallback = REFINEMENT_DENOISE_DEFAULT) {
+  const n = Number(raw)
+  if (!Number.isFinite(n)) return fallback
+  return Math.min(REFINEMENT_DENOISE_MAX, Math.max(REFINEMENT_DENOISE_MIN, Math.round(n * 100) / 100))
+}
+
+export function parseRefineExtensionFrame(raw: unknown, fallback = true) {
+  if (raw === undefined || raw === null || raw === '') return fallback
+  if (typeof raw === 'boolean') return raw
+  const value = String(raw).trim().toLowerCase()
+  if (value === 'true' || value === '1' || value === 'yes') return true
+  if (value === 'false' || value === '0' || value === 'no') return false
+  return fallback
+}
+
+export function parseSaveLosslessAnchor(raw: unknown, fallback = false) {
+  return parseRefineExtensionFrame(raw, fallback)
+}