[compiler][playground] (2/N) Config override panel (facebook#34344)

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## Summary

Part 2 of adding a "Config Override" panel to the React compiler
playground. Added sync from the config editor (still only accessible
with the "showConfig" param) to the main source code editor. Adding a
valid config to the editor will add/replace the `@OVERRIDE` pragma above
the source code. Additionally refactored the old implementation to
remove `useEffect`s and unnecessary renders.

Realized upon testing that the user experience is quite jarring,
planning to add a `sync` button in the next PR to fix this.

## How did you test this change?

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https://github.com/user-attachments/assets/a71b1b5f-0539-4c00-8d5c-22426f0280f9

DiffTrain build for [ac3e705](facebook@ac3e705)

Author: pull[bot]

compiled/facebook-www/REVISION

@@ -1 +1 @@
-7697a9f62e9959651337d70b46012fce69ef860a
+ac3e705a18696168acfcaed39dce0cfaa6be8836

compiled/facebook-www/REVISION_TRANSFORMS

@@ -1 +1 @@
-7697a9f62e9959651337d70b46012fce69ef860a
+ac3e705a18696168acfcaed39dce0cfaa6be8836

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

@@ -1418,7 +1418,7 @@ __DEV__ &&
     exports.useTransition = function () {
       return resolveDispatcher().useTransition();
     };
-    exports.version = "19.2.0-www-classic-7697a9f6-20250903";
+    exports.version = "19.2.0-www-classic-ac3e705a-20250902";
     "undefined" !== typeof __REACT_DEVTOOLS_GLOBAL_HOOK__ &&
       "function" ===
         typeof __REACT_DEVTOOLS_GLOBAL_HOOK__.registerInternalModuleStop &&

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

@@ -1418,7 +1418,7 @@ __DEV__ &&
     exports.useTransition = function () {
       return resolveDispatcher().useTransition();
     };
-    exports.version = "19.2.0-www-modern-7697a9f6-20250903";
+    exports.version = "19.2.0-www-modern-ac3e705a-20250902";
     "undefined" !== typeof __REACT_DEVTOOLS_GLOBAL_HOOK__ &&
       "function" ===
         typeof __REACT_DEVTOOLS_GLOBAL_HOOK__.registerInternalModuleStop &&

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

@@ -600,4 +600,4 @@ exports.useSyncExternalStore = function (
 exports.useTransition = function () {
   return ReactSharedInternals.H.useTransition();
 };
-exports.version = "19.2.0-www-classic-7697a9f6-20250903";
+exports.version = "19.2.0-www-classic-ac3e705a-20250902";

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

@@ -600,4 +600,4 @@ exports.useSyncExternalStore = function (
 exports.useTransition = function () {
   return ReactSharedInternals.H.useTransition();
 };
-exports.version = "19.2.0-www-modern-7697a9f6-20250903";
+exports.version = "19.2.0-www-modern-ac3e705a-20250902";

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

@@ -604,7 +604,7 @@ exports.useSyncExternalStore = function (
 exports.useTransition = function () {
   return ReactSharedInternals.H.useTransition();
 };
-exports.version = "19.2.0-www-classic-7697a9f6-20250903";
+exports.version = "19.2.0-www-classic-ac3e705a-20250902";
 "undefined" !== typeof __REACT_DEVTOOLS_GLOBAL_HOOK__ &&
   "function" ===
     typeof __REACT_DEVTOOLS_GLOBAL_HOOK__.registerInternalModuleStop &&

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

@@ -604,7 +604,7 @@ exports.useSyncExternalStore = function (
 exports.useTransition = function () {
   return ReactSharedInternals.H.useTransition();
 };
-exports.version = "19.2.0-www-modern-7697a9f6-20250903";
+exports.version = "19.2.0-www-modern-ac3e705a-20250902";
 "undefined" !== typeof __REACT_DEVTOOLS_GLOBAL_HOOK__ &&
   "function" ===
     typeof __REACT_DEVTOOLS_GLOBAL_HOOK__.registerInternalModuleStop &&