chore: Make rand usage deterministic and disable default features

[cdc-as81]

Summary

• Disable rand default features and explicitly enable only std, small_rng, and std_rng
• Replace remaining thread_rng usage with seeded RNGs in tests and benchmarks
• Use a deterministic default seed for benchmark population generation
• Remove the direct wasm getrandom dependency entry from the main crate manifest

[github-actions]

Benchmark Results

Hyperfine

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
large_sir::baseline	2.8 ± 0.1	2.7	3.1	1.00
large_sir::entities	6.7 ± 0.1	6.5	7.2	2.35 ± 0.07

Criterion

Regressions (slower)

Group	Bench	Param	Change	CI Lower	CI Upper
indexing	query_people_count_single_indexed_property_entities		84.375%	77.263%	91.346%
counts	multi_property_indexed_entities		37.309%	35.662%	39.071%
sample_entity	sample_entity_single_property_indexed	1000	20.316%	17.880%	22.738%
sample_entity	sample_entity_single_property_indexed	10000	15.480%	13.964%	16.867%
sample_entity	sample_entity_single_property_indexed	100000	14.165%	12.798%	15.679%
indexing	with_query_results_multiple_individually_indexed_properties_enti		12.199%	11.445%	12.927%
large_dataset	bench_query_population_derived_property_entities		6.336%	5.857%	6.795%
indexing	query_people_multiple_individually_indexed_properties_entities		3.270%	2.945%	3.657%
counts	single_property_indexed_entities		2.923%	2.545%	3.313%
examples	example-births-deaths		2.872%	2.434%	3.206%
counts	reindex_after_adding_more_entities		2.516%	1.542%	3.520%
sampling	sampling_multiple_l_reservoir_entities		2.449%	2.193%	2.723%
indexing	query_people_count_multiple_individually_indexed_properties_enti		1.931%	1.741%	2.109%
sampling	sampling_multiple_known_length_entities		1.470%	1.095%	1.859%

Improvements (faster)

Group	Bench	Param	Change	CI Lower	CI Upper
algorithm_benches	algorithm_sampling_single_known_length		-43.386%	-44.710%	-42.184%
algorithm_benches	algorithm_sampling_single_l_reservoir		-39.386%	-39.686%	-39.155%
algorithm_benches	algorithm_sampling_multiple_l_reservoir		-22.770%	-23.171%	-22.232%
counts	multi_property_unindexed_entities		-17.220%	-17.551%	-16.915%
counts	single_property_unindexed_entities		-9.123%	-11.027%	-7.135%
algorithm_benches	algorithm_sampling_multiple_known_length		-8.432%	-9.111%	-7.802%
counts	concrete_plus_derived_unindexed_entities		-7.682%	-9.815%	-5.573%
large_dataset	bench_query_population_multi_indexed_entities		-5.762%	-6.109%	-5.312%
sampling	count_and_sampling_single_known_length_entities		-4.076%	-4.465%	-3.497%
large_dataset	bench_match_entity		-4.029%	-4.430%	-3.687%
algorithm_benches	algorithm_sampling_single_rand_reservoir		-2.381%	-2.727%	-2.058%
sampling	sampling_single_known_length_entities		-1.624%	-2.190%	-1.157%

Unchanged / inconclusive (CI crosses 0%)

Group	Bench	Param	Change	CI Lower	CI Upper
sample_entity	sample_entity_multi_property_indexed	10000	3.728%	0.921%	6.996%
sample_entity	sample_entity_multi_property_indexed	1000	-2.413%	-5.258%	0.743%
sample_entity	sample_entity_multi_property_indexed	100000	1.725%	-0.381%	4.155%
large_dataset	bench_query_population_multi_unindexed_entities		-1.654%	-2.838%	-0.595%
sample_entity	sample_entity_single_property_unindexed	100000	-1.436%	-2.226%	-0.752%
indexing	with_query_results_single_indexed_property_entities		1.224%	0.635%	1.873%
large_dataset	bench_filter_indexed_entity		-1.189%	-8.918%	7.084%
sampling	sampling_single_unindexed_concrete_plus_derived_entities		-1.072%	-1.445%	-0.696%
indexing	with_query_results_indexed_multi-property_entities		-0.698%	-1.724%	0.095%
sampling	count_and_sampling_single_unindexed_concrete_plus_derived_entiti		0.649%	0.391%	0.889%
indexing	query_people_indexed_multi-property_entities		0.542%	0.269%	0.831%
sample_entity	sample_entity_single_property_unindexed	1000	-0.514%	-0.896%	-0.194%
sample_entity	sample_entity_single_property_unindexed	10000	0.485%	0.047%	1.103%
indexing	query_people_count_indexed_multi-property_entities		0.443%	0.016%	0.801%
large_dataset	bench_query_population_indexed_property_entities		-0.436%	-0.937%	-0.045%
sampling	sampling_single_unindexed_entities		-0.422%	-0.494%	-0.352%
large_dataset	bench_query_population_property_entities		-0.373%	-0.970%	0.212%
indexing	query_people_single_indexed_property_entities		0.355%	0.029%	0.824%
sampling	sampling_single_l_reservoir_entities		-0.353%	-1.475%	0.801%
examples	example-basic-infection		-0.337%	-0.914%	0.150%
counts	index_after_adding_entities		-0.298%	-0.545%	-0.031%
large_dataset	bench_filter_unindexed_entity		0.264%	-3.834%	3.882%
sample_entity	sample_entity_whole_population	1000	0.195%	-0.133%	0.555%
sample_entity	sample_entity_whole_population	10000	0.150%	-0.429%	0.577%
sample_entity	sample_entity_whole_population	100000	0.137%	-0.147%	0.455%
sampling	sampling_multiple_unindexed_entities		0.053%	-0.229%	0.328%

Not Compared (no baseline yet)

Group	Bench	Reason
(none)

[k88hudson-cfa]

Looks good, thanks!