feat(studio): add a global toggle to stop manual edits from auto-recording keyframes

Adds a control-bar toggle (next to the Add Keyframe diamond) that, when off,
makes a manual drag/resize/rotate/panel edit on an already-keyframed element
shift the whole tween by the edit's delta instead of inserting or updating a
keyframe at the playhead. The animation's shape is preserved, just moved.

Wired into every path that can auto-record a keyframe:
- canvas drag-to-move (tryGsapDragIntercept, reuses the existing Alt-drag
  "shift whole path" behavior)
- canvas resize/rotate (tryGsapResizeIntercept, tryGsapRotationIntercept)
- design-panel property edits (useAnimatedPropertyCommit)
- motion-path keyframe-node dragging (MotionPathOverlay), the path a plain
  click-drag on a keyframed element's canvas shape actually takes, since the
  element renders exactly at its current keyframe's position

The shared shift helper reuses synthesizeFlatTweenKeyframes for materializing
a flat tween instead of hand-rolling it, and lives in its own file
(gsapWholePropertyOffsetCommit.ts) to keep gsapDragCommit.ts under the
600-line cap, mirroring the existing gsapDragPositionCommit.ts split.

Fixes #1808

packages/studio/src/hooks/useAnimatedPropertyCommit.ts

@@ -17,6 +17,7 @@ import type { SetPatchProps } from "./gsapRuntimePatch";
 import { selectorFromSelection, computeElementPercentage } from "./gsapShared";
 import { resolveTweenStart, resolveTweenDuration } from "../utils/globalTimeCompiler";
 import { roundTo3 } from "../utils/rounding";
+import { commitWholePropertyOffset } from "./gsapWholePropertyOffsetCommit";
 
 interface CommitAnimatedPropertyDeps {
   selectedGsapAnimations: GsapAnimation[];
@@ -341,6 +342,27 @@ export function useAnimatedPropertyCommit(deps: CommitAnimatedPropertyDeps) {
         // keyframe would never land (the bug: scrolling depth on a keyframed element
         // just changed the constant instead of dropping a keyframe).
         if (elementHasKeyframes && anim) {
+          // With auto-keyframe off (#1808), nudge the whole tween instead of
+          // adding/updating a keyframe at the playhead.
+          if (!usePlayerStore.getState().autoKeyframeEnabled) {
+            const pct = computeElementPercentage(
+              usePlayerStore.getState().currentTime,
+              selection,
+              anim,
+            );
+            await commitWholePropertyOffset(
+              selection,
+              anim,
+              Object.fromEntries(
+                propEntries.filter((e): e is [string, number] => typeof e[1] === "number"),
+              ),
+              pct,
+              iframe,
+              { commitMutation: gsapCommitMutation },
+              `Edit ${primaryProp} (whole animation)`,
+            );
+            return;
+          }
           await commitKeyframeProps(
             selection,
             anim,