feat(flags): evaluate dynamic offline rules (FFL-2837 PR2)

[btthomas]

Pull request stack

1. Plan PR (#1345)
2. PR1: Rules engine boundary (#1346)
3. PR2: Dynamic offline evaluation (feat(flags): evaluate dynamic offline rules (FFL-2837 PR2) #1347) <- you are here
4. PR3: Provider API and documentation (#1348)

This description uses Simplified Technical English. Technical names and API names do not change.

Summary

This PR adds dynamic and mixed offline evaluation to FlagsClient.

• It stores precomputed and rules branches independently.
• It consumes the prepared protobuf object from configuration.rules.response directly.
• It keeps a valid branch when its sibling is invalid.
• It uses matching precomputed data first.
• It uses valid rules data second.
• It returns the applicable configuration error when no path is usable.
• It preserves missing and empty targeting keys as different values.
• It maps rules results to FlagDetails.
• It converts real assignments to TrackableAssignment.
• It keeps online and valid precomputed behavior unchanged.

Result behavior

• A malformed flag in matching precomputed data returns PARSE_ERROR before rules fallback.
• A malformed reached rules flag returns PARSE_ERROR.
• An absent flag returns FLAG_NOT_FOUND.
• Integer and numeric rules variations use the OpenFeature type number.
• An unsafe integer returns PARSE_ERROR instead of an imprecise number.

Tracking

A successful rules assignment uses the existing native assignment bridge.

• The SDK calls the bridge for each real assignment.
• Native code applies doLog to the exposure event.
• The SDK supplies an empty extraLogging object because the native bridge still requires it.
• Error and unmatched default results are not tracked.

TODO status

This PR adds no new TODO(FFL-2837) marker. It inherits the two PR1 follow-ups for regular-expression limits and the future peer-dependency minimum.

Checks

• Core TypeScript checks
• Changed-file ESLint and formatting checks
• Full core Jest suite

[sameerank]

According to the PR description

A flag that the upstream parser removes returns FLAG_NOT_FOUND

Once we consume the parser from DataDog/openfeature-js-client#344, malformed known flags should be preserved in precomputed.flagErrors and resolve to the coded default with PARSE_ERROR, matching core/browser. I see this PR already handles flagErrors before this fallback. Can you update the description and add an integration test using the upstream parser output?

[sameerank]

I think this should include PARSE_ERROR and should map to OpenFeature’s ParseError. Reserve GENERAL for failures that are more unexpected and harder to classify

[datadog-prod-us1-5]

✅ All CI checks and tests passed.

🎉 All green!

🧪 All tests passed
❄️ No new flaky tests detected

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