Add Suspensey Images behind a Flag (#32819)

We've known we've wanted this for many years and most of the
implementation was already done for Suspensey CSS. This waits to commit
until images have decoded by default or up to 500ms timeout (same as
suspensey fonts).

It only applies to Transitions, Retries (Suspense), Gesture Transitions
(flag) and Idle (doesn't exist). Sync updates just commit immediately.

`<img loading="lazy" src="..." />` opts out since you explicitly want it
to load lazily in that case.

`<img onLoad={...} src="..." />` also opts out since that implies you're
ok with managing your own reveal.

In the future, we may add an opt in e.g. `<img blocking="render"
src="..." />` that opts into longer timeouts and re-suspends even sync
updates. Perhaps also triggering error boundaries on errors.

The rollout for this would have to go in a major and we may have to
relax the default timeout to not delay too much by default. However, we
can also make this part of `enableViewTransition` so that if you opt-in
by using View Transitions then those animations will suspend on images.
That we could ship in a minor.

DiffTrain build for [efb22d8](efb22d8)

Author: sebmarkbage

compiled/facebook-www/REVISION

@@ -1 +1 @@
-c0f08ae74a46686f5718e9e6c511d27419fd632c
+efb22d8850382c3b53c1b2b8d22036d7e6cc9488

compiled/facebook-www/REVISION_TRANSFORMS

@@ -1 +1 @@
-c0f08ae74a46686f5718e9e6c511d27419fd632c
+efb22d8850382c3b53c1b2b8d22036d7e6cc9488

compiled/facebook-www/React-dev.classic.js

@@ -1538,7 +1538,7 @@ __DEV__ &&
     exports.useTransition = function () {
       return resolveDispatcher().useTransition();
     };
-    exports.version = "19.2.0-www-classic-c0f08ae7-20250403";
+    exports.version = "19.2.0-www-classic-efb22d88-20250404";
     "undefined" !== typeof __REACT_DEVTOOLS_GLOBAL_HOOK__ &&
       "function" ===
         typeof __REACT_DEVTOOLS_GLOBAL_HOOK__.registerInternalModuleStop &&

compiled/facebook-www/React-dev.modern.js

@@ -1538,7 +1538,7 @@ __DEV__ &&
     exports.useTransition = function () {
       return resolveDispatcher().useTransition();
     };
-    exports.version = "19.2.0-www-modern-c0f08ae7-20250403";
+    exports.version = "19.2.0-www-modern-efb22d88-20250404";
     "undefined" !== typeof __REACT_DEVTOOLS_GLOBAL_HOOK__ &&
       "function" ===
         typeof __REACT_DEVTOOLS_GLOBAL_HOOK__.registerInternalModuleStop &&

compiled/facebook-www/React-prod.classic.js

@@ -636,4 +636,4 @@ exports.useSyncExternalStore = function (
 exports.useTransition = function () {
   return ReactSharedInternals.H.useTransition();
 };
-exports.version = "19.2.0-www-classic-c0f08ae7-20250403";
+exports.version = "19.2.0-www-classic-efb22d88-20250404";

compiled/facebook-www/React-prod.modern.js

@@ -636,4 +636,4 @@ exports.useSyncExternalStore = function (
 exports.useTransition = function () {
   return ReactSharedInternals.H.useTransition();
 };
-exports.version = "19.2.0-www-modern-c0f08ae7-20250403";
+exports.version = "19.2.0-www-modern-efb22d88-20250404";

compiled/facebook-www/React-profiling.classic.js

@@ -640,7 +640,7 @@ exports.useSyncExternalStore = function (
 exports.useTransition = function () {
   return ReactSharedInternals.H.useTransition();
 };
-exports.version = "19.2.0-www-classic-c0f08ae7-20250403";
+exports.version = "19.2.0-www-classic-efb22d88-20250404";
 "undefined" !== typeof __REACT_DEVTOOLS_GLOBAL_HOOK__ &&
   "function" ===
     typeof __REACT_DEVTOOLS_GLOBAL_HOOK__.registerInternalModuleStop &&

compiled/facebook-www/React-profiling.modern.js

@@ -640,7 +640,7 @@ exports.useSyncExternalStore = function (
 exports.useTransition = function () {
   return ReactSharedInternals.H.useTransition();
 };
-exports.version = "19.2.0-www-modern-c0f08ae7-20250403";
+exports.version = "19.2.0-www-modern-efb22d88-20250404";
 "undefined" !== typeof __REACT_DEVTOOLS_GLOBAL_HOOK__ &&
   "function" ===
     typeof __REACT_DEVTOOLS_GLOBAL_HOOK__.registerInternalModuleStop &&