[DataLoader] Add ArrivalOrder API and batch_size support

[robreeves]

Summary

Re-introduce the ArrivalOrder scan order and batch_size parameter that were removed in #504. The original removal was necessary because the fork dependency (sumedhsakdeo/iceberg-python) made it ineligible for use internally at LI. Now that li-pyiceberg==0.11.3 includes the ArrivalOrder API from upstream (apache/iceberg-python#3046), we can restore the functionality using an approved registry dependency.

In a future PR, we will add support for streaming multiple splits concurrently using ArrivalOrder with concurrent_streams > 1.

Changes

• Client-facing API Changes
• Internal API Changes
• Bug Fixes
• New Features
• Performance Improvements
• Code Style
• Refactoring
• Documentation
• Tests

pyproject.toml — Bump li-pyiceberg from 0.11.2 to 0.11.3 which includes the ArrivalOrder API.

data_loader.py — Re-add batch_size parameter to OpenHouseDataLoader.__init__, forwarded to each DataLoaderSplit.

data_loader_split.py — Re-add ArrivalOrder import and batch_size parameter. to_record_batches() now uses order=ArrivalOrder(concurrent_streams=1, batch_size=self._batch_size).

uv.lock — Regenerated to resolve li-pyiceberg==0.11.3 from the internal registry.

Tests — Re-add test_arrival_order.py (verifies ScanOrder class hierarchy and ArrowScan.to_record_batches with order parameter). Re-add batch_size tests in test_data_loader.py, test_data_loader_split.py, and integration_tests.py.

Testing Done

• Manually Tested on local docker setup. Please include commands ran, and their output.
• Added new tests for the changes made.
• Updated existing tests to reflect the changes made.
• No tests added or updated. Please explain why. If unsure, please feel free to ask for help.
• Some other form of testing like staging or soak time in production. Please explain.

make verify passes — 202 tests pass, lint, format, and mypy all green.

Additional Information

• Breaking Changes
• Deprecations
• Large PR broken into smaller PRs, and PR plan linked in the description.

batch_size is re-added to OpenHouseDataLoader and DataLoaderSplit. This is additive (new optional parameter with default None), so existing callers are unaffected.