Pin matching React Canary versions in browser demos

Author: aurorascharff

src/content/reference/react-dom/browser.md

@@ -169,8 +169,8 @@ iframe {
 ```json package.json hidden
 {
   "dependencies": {
-    "react": "canary",
-    "react-dom": "canary",
+    "react": "19.3.0-canary-eafeac09-20260819",
+    "react-dom": "19.3.0-canary-eafeac09-20260819",
     "react-scripts": "latest"
   },
   "scripts": {

src/content/reference/react/Suspense.md

@@ -2478,8 +2478,8 @@ iframe {
 ```json package.json hidden
 {
   "dependencies": {
-    "react": "canary",
-    "react-dom": "canary",
+    "react": "19.3.0-canary-eafeac09-20260819",
+    "react-dom": "19.3.0-canary-eafeac09-20260819",
     "react-scripts": "latest"
   },
   "scripts": {

src/content/reference/react/use.md

@@ -1432,8 +1432,8 @@ iframe {
 ```json package.json hidden
 {
   "dependencies": {
-    "react": "canary",
-    "react-dom": "canary",
+    "react": "19.3.0-canary-eafeac09-20260819",
+    "react-dom": "19.3.0-canary-eafeac09-20260819",
     "react-scripts": "latest"
   },
   "scripts": {