chore: Update sdk_metadata features

[devin-ai-integration]

Summary

Adds features metadata to .sdk_metadata.json for both the C++ Client SDK and C++ Server SDK. Feature names use canonical camelCase keys from sdk-meta/products/feature_info.json, and introduction versions are sourced from the SDK features documentation table and verified against the repo's CHANGELOGs where applicable.

For features that predate the cpp-sdks monorepo (3.x), introduction versions were cross-referenced against the legacy c-client-sdk and c-server-sdk CHANGELOGs.

C++ Client SDK (12 features): allFlags, appMetadata, bigSegments, contexts, experimentation, flagChanges, inlineContextCustomEvents, offlineMode, privateAttrs, relayProxyProxy, track, variationDetail

C++ Server SDK (16 features): allFlags, appMetadata, contexts, experimentation, fileDataSource, hooks, inlineContextCustomEvents, offlineMode, privateAttrs, relayProxyDaemon, relayProxyProxy, storingData, storingDataRedis, testDataSource, track, variationDetail

Updates since last revision

Added features (verified against repo CHANGELOGs):

• hooks added to server SDK at 3.10 — confirmed via libs/server-sdk/CHANGELOG.md entry "Add support for hooks" under ## [3.10.0]
• offlineMode added to client SDK at 1.0 — see version correction below

Version corrections based on legacy c-client-sdk analysis (per reviewer feedback to check pre-3.x repos):

• offlineMode (client SDK): 3.0 → 1.0 — offline mode existed in the legacy c-client-sdk from its initial release. The cpp-sdks monorepo re-added it in prerelease 0.2.0, but since the feature was available in the SDK lineage since 1.0, that version is used.
• variationDetail (client SDK): 1.0 → 1.1 — the legacy c-client-sdk explicitly added evaluation reasons / VariationDetail in version 1.1.0.

Legacy repo analysis notes:

• All server SDK versions checked out correctly against c-server-sdk (fileDataSource, testDataSource at 2.6; storingData/storingDataRedis/relayProxyDaemon at 1.2; experimentation at 2.4).
• multiEnv was present in c-client-sdk 1.2.0 but does not appear to be supported in the current cpp-sdks client SDK (no matching code found), so it was not added.

Review & Testing Checklist for Human

• Verify variationDetail: "1.1" for client SDK vs "1.0" for server SDK — the asymmetry is because c-client-sdk explicitly added evaluation reasons in 1.1.0, while the c-server-sdk appears to have had it from 1.0.0. Confirm this is correct, or whether both should be the same.
• Verify offlineMode: "1.0" for client SDK — changed from "3.0" based on legacy c-client-sdk analysis. Confirm using the legacy version (rather than the cpp-sdks monorepo version) is the desired convention.
• Validate bigSegments: "1.0" for client SDK — the docs say "All" (meaning all versions). "1.0" was used as the first stable release version. The earliest git tag is launchdarkly-cpp-client-v0.0.0, so confirm "1.0" is the correct first stable version.
• Confirm storingData and storingDataRedis both at "1.2" — the docs say "1.2 (Redis)" for C++ server storing data. Verify Redis was the only store supported and that "1.2" is correct for both.
• Check for any remaining missing features — features like pluginSupport, omitAnonContexts, and pollingResponseCompression are not included. Verify none of these have been added in recent releases.
• Validate JSON is well-formed and features are in alphabetical order.

Notes

• This is part of a batch update across 9 SDK repositories.
• Requested by: Aaron Zeisler
• Link to Devin session

[devin-ai-integration]

🤖 Devin AI Engineer

I'll be helping with this pull request! Here's what you should know:

✅ I will automatically:

• Address comments on this PR. Add '(aside)' to your comment to have me ignore it.
• Look at CI failures and help fix them

Note: I can only respond to comments from users who have write access to this repository.

⚙️ Control Options:

• Disable automatic comment and CI monitoring

[kinyoklion]

For support before client-side 3.x check this repository: https://github.com/launchdarkly/c-client-sdk
For server-side before 3.x check this repository: https://github.com/launchdarkly/c-server-sdk

Use its git commit history and changelogs for those repositories.

[devin-ai-integration]

@kinyoklion Thanks for the pointer! I cloned both legacy repos and cross-referenced their CHANGELOGs against the features in this PR. Here's what I found and changed:

Corrections made (client SDK):

• offlineMode: 3.0 → 1.0 — offline mode existed in the legacy c-client-sdk from its initial release
• variationDetail: 1.0 → 1.1 — c-client-sdk explicitly added evaluation reasons / VariationDetail in version 1.1.0

Server SDK — all versions verified correct:

• fileDataSource at 2.6 (c-server-sdk 2.6.0: "Added integrations/file_data.h")
• testDataSource at 2.6 (c-server-sdk 2.6.0: "Added integrations/test_data.h")
• storingData / storingDataRedis / relayProxyDaemon at 1.2 (c-server-sdk 1.2.0)
• experimentation at 2.4 (c-server-sdk 2.4.0)

Other notes:

• multiEnv was present in c-client-sdk 1.2.0 (LDConfigAddSecondaryMobileKey) but I couldn't find any matching code in the current cpp-sdks client SDK, so it was not added.
• The asymmetry between variationDetail: "1.1" (client) vs "1.0" (server) is because c-client-sdk added it in 1.1.0 while c-server-sdk appears to have had it from 1.0.0. Please verify this is correct.