fix(sync): keep the catalog writer alive for the VACINACAO phase

[devgtv]

Summary

SyncEngine.run() has a single consumer of write_queue — the serial catalog_writer coroutine — which shuts itself down after seeing writers_total sentinels.

The "no producers" branch queued the writer's shutdown sentinel too early:

else:
    for _ in range(workers):
        await raw_queue.put(None)      # stops the processors
if not ftp_tasks and not gov_workers_tasks:
    for _ in range(workers):
        await write_queue.put(None)    # stops the writer

writers_total = max(1, len(gov_workers_tasks))   # == 1 here

writers_total is 1 when there are no gov items, so the writer consumed one sentinel and exited. The second block is a copy-paste of the first, which is correct for raw_queue.

Impact

VACINACAO items are deliberately deferred to a serial phase that runs after the concurrent drain and pushes onto write_queue (as does the retry pass). With the writer already gone, those entries had no reader:

1. The parquet was uploaded to S3, but no catalog row was written and no SyncOutcome was emitted — the artifact stayed invisible to PySUS and the run reported nothing happening.
2. Once the bounded queue (maxsize=workers*2) filled, put blocked forever. The run hung with no timeout.

This affects any run whose pending items are all VACINACAO — e.g. sync_clients.py --saude-only, or run(datasets=["VACINACAO"]). The existing tests always pair VACINACAO with a dadosgov item, which keeps gov_workers_tasks non-empty and hides the bug.

Fix

The writer's single shutdown sentinel is now queued at the end of run(), immediately before awaiting the writer, and writers_total is set to 1 to match the one consumer that exists.

Test

test_run_vacinacao_only_syncs_every_file runs a VACINACAO-only sync of 6 items and asserts all 6 are reported uploaded and all 6 reach the catalog. It fails with assert 0 == 6 against the previous code.

• 1734 passed, 6 skipped
• black and isort clean