feat(studio): stage 7 step 3b — SDK shadow dispatch parity mode (#1450)

* feat(studio): stage 7 step 3b — SDK shadow dispatch parity mode

Wire onDomEditPersisted callback from useDomEditCommits into useDomEditSession,
calling reportShadowDispatch (flag-gated via VITE_STUDIO_SDK_SHADOW_ENABLED) to
dispatch equivalent SDK ops alongside the server patch path and emit
sdk_shadow_dispatch telemetry with mismatch details.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

* fix(studio/sdkShadow): catch dispatch errors, return dispatch_error mismatch

Wrap the dispatch loop in try/catch so a throwing SDK dispatch never
propagates to Studio UX. Returns dispatched:false with kind="dispatch_error"
and the error message for telemetry. One new TDD test (RED→GREEN verified).

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

* fix(studio): batch shadow dispatch, rename runShadowDispatch, add PatchOperation import

Wrap the shadow dispatch loop in session.batch() so a mid-loop throw
cannot leave the SDK session in a partially-applied state. Without the
batch boundary, one failing op would update some elements but not
others, diverging the shadow session from the real one.

Rename reportShadowDispatch → runShadowDispatch to eliminate the
misleading 'report' prefix — the function mutates the SDK session, it
is not read-only. Update the only caller (useDomEditSession).

Add missing PatchOperation import to useDomEditCommits (the type was
already used in the onDomEditPersisted interface but never imported).

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Co-authored-by: Miguel Ángel <miguel07alm@protonmail.com>

* docs(studio/sdkShadow): note persist:error drift risk in parity comparisons

Also remove unused re-exports from useDomEditCommits (GSAP_CSS_FALLBACK_BLOCKED_MESSAGE
and PersistDomEditOperations — fallow confirmed 0 consumers) and suppress the
Vite ?raw import in sdk-playground that fallow can't resolve statically.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Co-authored-by: Miguel Ángel <miguel07alm@protonmail.com>

---------

Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>
Co-authored-by: Miguel Ángel <miguel07alm@protonmail.com>

packages/studio/src/hooks/useDomEditCommits.ts

@@ -9,14 +9,12 @@ import { buildDomEditPatchTarget, type DomEditSelection } from "../components/ed
 import { fontFamilyFromAssetPath, type ImportedFontAsset } from "../components/editor/fontAssets";
 import type { EditHistoryKind } from "../utils/editHistory";
 import type { PersistDomEditOperations } from "./domEditCommitTypes";
+import type { PatchOperation } from "../utils/sourcePatcher";
 import { useDomEditPositionPatchCommit } from "./useDomEditPositionPatchCommit";
 import { useDomEditTextCommits } from "./useDomEditTextCommits";
 import { useDomGeometryCommits } from "./useDomGeometryCommits";
 import { useElementLifecycleOps } from "./useElementLifecycleOps";
 
-// Re-export so existing consumers keep their import path
-export { GSAP_CSS_FALLBACK_BLOCKED_MESSAGE } from "./useDomGeometryCommits";
-
 // ── Helpers ──
 
 function formatUnsafeFieldList(fields: Array<{ path: string }>): string {
@@ -40,8 +38,6 @@ function formatPatchRejectionMessage(body: { error?: string; fields?: string[] }
   return `Couldn't save edit: ${body.error}${suffix}`;
 }
 
-// ── Types ──
-
 interface RecordEditInput {
   label: string;
   kind: EditHistoryKind;
@@ -49,8 +45,6 @@ interface RecordEditInput {
   files: Record<string, { before: string; after: string }>;
 }
 
-export type { PersistDomEditOperations } from "./domEditCommitTypes";
-
 export interface UseDomEditCommitsParams {
   activeCompPath: string | null;
   previewIframeRef: React.MutableRefObject<HTMLIFrameElement | null>;
@@ -77,10 +71,10 @@ export interface UseDomEditCommitsParams {
     target: HTMLElement,
     options?: { preferClipAncestor?: boolean },
   ) => Promise<DomEditSelection | null>;
+  /** Stage 7 Step 3b: called after a successful server-side element patch. */
+  onDomEditPersisted?: (selection: DomEditSelection, operations: PatchOperation[]) => void;
 }
 
-// ── Hook ──
-
 export function useDomEditCommits({
   activeCompPath,
   previewIframeRef,
@@ -99,6 +93,7 @@ export function useDomEditCommits({
   clearDomSelection,
   refreshDomEditSelectionFromPreview,
   buildDomSelectionFromTarget,
+  onDomEditPersisted,
 }: UseDomEditCommitsParams) {
   const resolveImportedFontAsset = useCallback(
     (fontFamilyValue: string): ImportedFontAsset | null => {
@@ -220,6 +215,7 @@ export function useDomEditCommits({
         coalesceKey: options?.coalesceKey,
         files: { [targetPath]: { before: originalContent, after: finalContent } },
       });
+      onDomEditPersisted?.(selection, operations);
 
       if (!options?.skipRefresh) {
         reloadPreview();
@@ -233,6 +229,7 @@ export function useDomEditCommits({
       domEditSaveTimestampRef,
       reloadPreview,
       showToast,
+      onDomEditPersisted,
     ],
   );