feat: wire FDv2 into v3 contract tests, with CI

[beekld]

Adds FDv2 wiring to the server contract-test service so the v3 SDK test harness can exercise the FDv2 code paths, plus a CI job that runs the v3 harness on every change.

• New dataSystem block on ConfigParams covering harness-provided initializers, synchronizers, and fdv1 fallback.
• Entity manager dispatches FDv2 vs BackgroundSync based on the dataSystem presence
• fdv1-fallback capability advertised by the service
• Empty test-suppressions-fdv2.txt
• New CI job runs the v3.0.0-alpha.3 harness

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Note

Low Risk
Changes are limited to contract-test adapters, CI, and test suppressions; production SDK behavior is only exercised indirectly via existing builders.

Overview
Adds v3 SDK contract-test coverage for FDv2 by extending the harness config model and routing client creation through FDv2 when the harness sends a dataSystem block.

Contract-test service: ConfigParams gains optional dataSystem (initializers, synchronizers, fdv1Fallback, payloadFilter). EntityManager::create chooses FDv2 via BuildFDv2 when dataSystem is present; otherwise it keeps the existing BackgroundSync path in a refactored BuildBackgroundSync. FDv2 mapping wires streaming/polling synchronizers and initializers, explicit or derived FDv1 fallback (polling URL on global endpoints), and advertises the fdv1-fallback capability.

CI: New contract-tests-fdv2 and contract-tests-fdv2-curl jobs build server-tests, start the service, and run the v3.0.0-alpha.3 harness with test-suppressions-fdv2.txt (skipped scenarios for TTL vs terminal FDv1 fallback and unexposed FDv2 payload filter URL tests).

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Cursor Bugbot has reviewed your changes using default effort and found 1 potential issue.

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Explicit fdv1Fallback skips URL

Medium Severity

When dataSystem.fdv1Fallback is present but has no baseUri, BuildFDv2 enables FDv1 fallback without updating ServiceEndpoints polling URL. The synchronizer-derived polling URL logic runs only when fdv1Fallback is omitted, so the same harness config can point FDv1 polling at the default endpoint instead of the mock synchronizer URL.

Additional Locations (1)

• contract-tests/server-contract-tests/src/entity_manager.cpp#L70-L100

 

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