[feature] Coordinate GammaLake predicate pushdown

[gauglertodd]

Coordinates predicate pushdown through the polars-io-tools adapter so filters are applied as early as correctness permits. Canonical-key joins preserve alignment; runtime/as-of paths retain neighbor context, and timezone-aware temporal predicates bypass the upstream 0.2.1 naive-datetime translation.

Stacked PR 18/19. Base: parity/17-lazy-multi-source.

[github-actions]

Test Results

138 tests  +13   138 ✅ +13   42s ⏱️ ±0s
  1 suites ± 0     0 💤 ± 0 
  1 files   ± 0     0 ❌ ± 0 

Results for commit f81a729. ± Comparison against base commit ce0265a.

This pull request removes 1 and adds 14 tests. Note that renamed tests count towards both.

gammalake.tests.test_multi_source ‑ test_rejects_mismatched_filtered_heights

gammalake.tests.test_gamma_feature_lake.TestGammaFeatureLake ‑ test_as_of_features_compute_before_lazy_filter
gammalake.tests.test_gamma_feature_lake.TestGammaFeatureLake ‑ test_feature_filter_matches_filtering_unmaterialized_result
gammalake.tests.test_gamma_feature_lake.TestGammaFeatureLake ‑ test_mixed_dense_sparse_read_aligns_values_to_keys
gammalake.tests.test_gamma_feature_lake.TestGammaFeatureLake ‑ test_multi_source_filter_plan_and_exact_equivalence
gammalake.tests.test_gamma_feature_lake.TestGammaFeatureLake ‑ test_multi_sparse_read_aligns_when_tails_differ
gammalake.tests.test_gamma_feature_lake.TestGammaFeatureLake ‑ test_multi_table_read_preserves_horizontal_alignment[False]
gammalake.tests.test_gamma_feature_lake.TestGammaFeatureLake ‑ test_multi_table_read_preserves_horizontal_alignment[True]
gammalake.tests.test_gamma_feature_lake.TestGammaFeatureLake ‑ test_non_leading_primary_sort_key_preserves_alignment_and_bounds
gammalake.tests.test_gamma_feature_lake.TestGammaFeatureLake ‑ test_projection_only_aggregation_remains_correct
gammalake.tests.test_gamma_feature_lake.TestGammaFeatureLake ‑ test_runtime_features_compute_before_lazy_filter
…