chore: Update sdk_metadata features

[devin-ai-integration]

Requirements

• I have added test coverage for new or changed functionality — N/A, metadata-only change
• I have followed the repository's pull request submission guidelines
• I have validated my changes against all supported platform versions — N/A, metadata-only change

Related issues

Part of a cross-repo effort to populate the features field in .sdk_metadata.json for all LaunchDarkly SDKs.

Describe the solution you've provided

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. Feature keys use the canonical camelCase names from sdk-meta/products/feature_info.json, and introduction versions are sourced from the SDK features documentation table (JavaScript-based client-side SDKs → React Web column) and verified against the repository's CHANGELOG.

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

Updates since last revision

Added two new features, verified against CHANGELOG.md:

• hooks: introduced in 3.7 — confirmed via CHANGELOG entry "Add hook and plugin support" under ## [3.7.0]. Note: this is the LaunchDarkly evaluation hooks feature, distinct from the React hooks (useState/useEffect) added in 2.11.0.
• perContextSummaryEvents: introduced in 3.8 — confirmed via CHANGELOG entry "Add support for per-context summary events" under ## [3.8.0].

Updated three feature versions per reviewer guidance that version 2.9 was the first actual react-client-sdk release (prior versions were part of js-client-sdk):

• bigSegments: 1.0 → 2.9
• experimentation: 1.0 → 2.9
• track: 1.0 → 2.9

Human review checklist

• Verify pluginSupport: "3.7" — mapped from the "Observability plugin" row in the docs table. Introduced in the same release as hooks. Confirm this mapping is correct.
• Spot-check a few introduction versions against the repo's CHANGELOG or release history (e.g., bootstrapping: "2.9.5", relayProxyProxy: "2.20.2", contexts: "3.0").
• Confirm no supported features are missing — the docs table shows empty cells for migrations, offlineMode, autoEnvAttrs, fileDataSource, testDataSource, webProxy, and others. Verify these are truly unsupported by this SDK.

Describe alternatives you've considered

N/A — follows the established pattern from other SDKs (e.g., js-core, go-server-sdk).

Additional context

• Link to Devin session
• Requested by: Aaron Zeisler

[devin-ai-integration]

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