chore: Update sdk_metadata features (#379)

Adds a features map to the react-client-sdk entry in .sdk_metadata.json, documenting which SDK features are supported and the version each was introduced.

15 features included: allFlags, appMetadata, bigSegments, bootstrapping, contexts, experimentation, flagChanges, hooks, perContextSummaryEvents, pluginSupport, privateAttrs, relayProxyProxy, secureMode, track, variationDetail.

Author: devin-ai-integration[bot]

.sdk_metadata.json

@@ -10,6 +10,23 @@
       "wrapperNames": ["react-client-sdk"],
       "releases": {
         "tag-prefix": "launchdarkly-react-client-sdk-"
+      },
+      "features": {
+        "allFlags": { "introduced": "2.9" },
+        "appMetadata": { "introduced": "2.26" },
+        "bigSegments": { "introduced": "2.9" },
+        "bootstrapping": { "introduced": "2.9.5" },
+        "contexts": { "introduced": "3.0" },
+        "experimentation": { "introduced": "2.9" },
+        "flagChanges": { "introduced": "2.9" },
+        "hooks": { "introduced": "3.7" },
+        "perContextSummaryEvents": { "introduced": "3.8" },
+        "pluginSupport": { "introduced": "3.7" },
+        "privateAttrs": { "introduced": "2.9" },
+        "relayProxyProxy": { "introduced": "2.9" },
+        "secureMode": { "introduced": "2.18" },
+        "track": { "introduced": "2.9" },
+        "variationDetail": { "introduced": "2.21" }
       }
     }
   }