feat(studio): extend SDK shadow to delete/timing/gsap-add + default on (#1473)

* feat(studio): default SDK shadow dispatch on for parity telemetry

Shadow mode keeps the server patch path authoritative (no user-visible
change) and emits sdk_shadow_dispatch parity signal. Default it on so we
collect addressing/serialize-drift telemetry from all traffic before any
cutover. Disable via VITE_STUDIO_SDK_SHADOW_ENABLED=false.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

* feat(studio): shadow parity for delete/timing/gsap ops + wire delete

Extends shadow visibility past the property-edit path. Adds a can()-first
shadow core (pure addressing/validity pre-check, works even for GSAP which
has no snapshot value) plus runShadowDelete/runShadowTiming/runShadowGsapTween.
Parity coverage: delete = getElement null (full); timing = snapshot
start/duration/trackIndex (full); gsap = can()+dispatch+returned-id only
(animationIds is a stub, tween values are script-level — full fidelity needs
serialize() round-trip diffing, out of scope).

Wires the delete runner end-to-end via an onElementDeleted callback
(useDomEditSession → useDomEditCommits → useElementLifecycleOps), fired after
the server delete succeeds. Server stays authoritative. Timing/GSAP wiring
follows (each needs threading sdkSession into useTimelineEditing /
useGsapScriptCommits).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

* feat(studio): wire timing + GSAP-add shadow dispatch

Timing: thread sdkSession into useTimelineEditing; fire runShadowTiming after
move/resize persist (server authoritative). Moved the useSdkSession call above
useTimelineEditing so both share the single session (no duplicate).

GSAP: thread sdkSession through useGsapScriptCommits → useGsapAnimationOps;
shadow addGsapAnimation via runShadowGsapTween after the server add. Only the
add path is shadowed — delete/update key on the server's animationId, which
doesn't resolve in the SDK's independent id-space (would emit false
cannot_dispatch). "set" has no SDK method, so it's skipped.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

* fix(studio): address #1473 review — no-persist shadow session + fallow gate

Blocker (Rames): the shadow runners dispatched on the live persisted SDK
session, so each shadow op fired the persist queue → an HTTP write of the SDK's
serialize() output, clobbering the studio's authoritative write (default-on
shipped this). Fix: open the shadow session WITHOUT persist — it reads from the
server but never writes back. Shadow dispatches mutate the in-memory model only
and are discarded on the next reload-on-change. Cutover (Step 3c+) must re-add
persist together with self-write suppression. No persist consumer exists in
this stack (cutover is not in main), so this is safe and keeps default-on.

Fallow CI gate (Miguel):
- drop unused `export` on RecordEditInput (dead-type)
- suppress pre-existing CRAP with reasons: commitMutation, addGsapAnimation;
  file-level complexity on useTimelineEditing (shadow .then() branches nudge
  several callbacks over threshold — telemetry-only)
- suppress 3 pre-existing clones surfaced by adjacent edits (save-error
  formatter, prop-drilling passthrough, file-change reload handler)

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

* fix(studio): scrub user content from shadow property-path telemetry

Addresses #1473 review concern (Rames): inline-style and text-content edits
put user content into the sdk_shadow_dispatch mismatch expected/actual fields.
Redact before emit — text-content values fully redacted (length only), others
length-capped at 64. The in-memory parity result keeps raw values, so the
parity logic and tests are unaffected.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

packages/studio/src/hooks/useDomEditCommits.ts

@@ -31,6 +31,9 @@ async function readErrorResponseBody(
 
 function formatPatchRejectionMessage(body: { error?: string; fields?: string[] } | null): string {
   if (!body?.error) return "Couldn't save edit";
+  // Pre-existing clone of the GSAP save-error formatter (gsapScriptCommitHelpers);
+  // surfaced here by this PR's adjacent edits, not introduced by it.
+  // fallow-ignore-next-line code-duplication
   const fields = Array.isArray(body.fields)
     ? body.fields.filter((field): field is string => typeof field === "string")
     : [];
@@ -73,6 +76,8 @@ export interface UseDomEditCommitsParams {
   ) => Promise<DomEditSelection | null>;
   /** Stage 7 Step 3b: called after a successful server-side element patch. */
   onDomEditPersisted?: (selection: DomEditSelection, operations: PatchOperation[]) => void;
+  /** Stage 7 Step 3b: called after a successful server-side element delete. */
+  onElementDeleted?: (selection: DomEditSelection) => void;
 }
 
 export function useDomEditCommits({
@@ -94,6 +99,7 @@ export function useDomEditCommits({
   refreshDomEditSelectionFromPreview,
   buildDomSelectionFromTarget,
   onDomEditPersisted,
+  onElementDeleted,
 }: UseDomEditCommitsParams) {
   const resolveImportedFontAsset = useCallback(
     (fontFamilyValue: string): ImportedFontAsset | null => {
@@ -290,6 +296,7 @@ export function useDomEditCommits({
     reloadPreview,
     clearDomSelection,
     commitPositionPatchToHtml,
+    onElementDeleted,
   });
 
   return {