Enhance vector clock performance

[fbac]

Change SelectVectorClock to return gateway_time with latest originator_sequence_id per originator_node_id and initialize originator stream cursors to improve vector clock performance

This updates the vector clock query and stream initialization to use gateway timestamps instead of raw envelopes. - Replace SelectVectorClock SQL with a lateral join that returns originator_node_id, latest originator_sequence_id, and gateway_time, and regenerate query code to scan into GatewayTime time.Time in envelopes.sql.go and update the SQL in envelopes.sql. - Create indexes idx_gateway_envelopes_vector_clock and idx_gateway_envelopes_originator_node_id in 00016_vector_clock.up.sql and drop them in 00016_vector_clock.down.sql. - Introduce a lightweight cursor (sequenceID, timestampNS) and refactor originatorStream to track validation state using the cursor instead of the last envelope in originator_stream.go with matching test adjustments in originator_stream_test.go. - Initialize stream position from SelectVectorClock by constructing a cursor using OriginatorSequenceID and GatewayTime.UnixNano() in syncWorker.setupStream in sync_worker.go.

📍Where to Start

Start with syncWorker.setupStream in sync_worker.go, then review the SelectVectorClock changes in envelopes.sql and the regenerated code in envelopes.sql.go.

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Macroscope summarized 8c414bd.

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[neekolas]

Are there similar issues with SelectGatewayEnvelopes? That's the one that gets used the most