Fix deterministic ordering for multi-instrument market shards

[hjcud]

Closes #88.

Root cause

The Development manifest is valid producer output: 8 immutable shards, 7 empty, and shard 04 contains 546 rows for 2 instruments ordered by (instrument_id, bar_start_at). The consumer incorrectly required timestamps alone to increase across every row and object, so the timestamp reset at the second instrument was rejected as INPUT_DATASET_UNREADABLE.

Fix

• verify all object hashes, row counts, schemas, and logical cross-object schema compatibility before yielding any row;
• allow either supported deterministic layout per object: (instrument_id, bar_start_at) or the existing (bar_start_at, instrument_id) layout;
• reject duplicates or a stream that ceases to be monotonic in both layouts;
• reset order proof at each immutable object boundary;
• preserve bounded Parquet batch decoding and event-clock global market-time ordering;
• pin the exact INT03 shape through iter_batches -> bar_events_from_batches -> MarketEventClock, including shard-local schema metadata and empty shards.

Verification

• full Docker-free pytest suite: passed;
• full Docker integration suite: passed; the 10 SQS tests skipped without a fixed service endpoint were rerun against LocalStack 4.7.0 and all 10 passed;
• python -m mypy: passed;
• python -m ruff check src tests: passed;
• exact read-only Development shadow replay, proposed source SHA-256 7a907241eddea0c24742470e8ee99753dea83f19cb2ad992cccad34c78134c60:
  • SSM ecceb57f-b345-4a58-a96d-ea827ed6d115: COMPLETED;
  • SSM 2f4dbde9-2c35-4c36-97ba-4ca29dfe3ab5: COMPLETED;
  • both used manifest 7f7113c9-3b02-4098-97ec-0baa07e2b3b0, policy development-official-backtest-2026-q3-v2, all 8 exact S3 versions, 546 rows, 273 evaluation steps, and produced replay digest a09631d8037d774297dd0da75223e3b8774e1c5d3e6426b418d7ecc227121499;
  • zero result, database, queue, or object-store writes.

The failed public run and all existing DLQ messages remain untouched. This PR intentionally does not update the root submodule pointer or deploy Development.