feat(ai): expose configurable HNSW search breadth

[jimezesinachi]

AI searches currently omit DB's configurable HNSW search breadth, so callers cannot tune ef_search through the AI API. Add optional ef_search to AI GetSimN and forward it unchanged to DB. Reject zero before model inference; omission preserves the server default max(closest_n, 50), and DB raises positive values to at least closest_n for HNSW. Other algorithms ignore positive values.

Update Rust, Python, Go, and TypeScript bindings, existing Rust request constructors, and the similarity-search parameter documentation. Existing DSL queries continue to omit the field.

Validation:

• Focused AI test passed: optional-field roundtrips and rejection of zero before inference, without loading models.
• All 38 DSL tests passed.
• Python AI request and pipeline roundtrips passed.
• Go AI query and service bindings compiled.
• Rust/Python formatting and diff whitespace checks passed.

[github-actions]

Test Results

508 tests   508 ✅  21m 56s ⏱️
 43 suites    0 💤
  4 files      0 ❌

Results for commit e886bc1.

♻️ This comment has been updated with latest results.

[github-actions]

Benchmark Results

group                                                        main                                   pr
-----                                                        ----                                   --
predicate_query_with_index/size_100                          1.07      2.7±0.01µs        ? ?/sec    1.00      2.5±0.00µs        ? ?/sec
predicate_query_with_index/size_1000                         1.02     25.4±0.05µs        ? ?/sec    1.00     24.9±0.05µs        ? ?/sec
predicate_query_with_index/size_10000                        1.00    250.7±0.20µs        ? ?/sec    1.00    250.9±1.08µs        ? ?/sec
predicate_query_with_index/size_100000                       1.03      4.9±0.17ms        ? ?/sec    1.00      4.8±0.22ms        ? ?/sec
predicate_query_without_index/size_100                       1.02      5.1±0.00µs        ? ?/sec    1.00      5.0±0.00µs        ? ?/sec
predicate_query_without_index/size_1000                      1.01     46.9±0.18µs        ? ?/sec    1.00     46.6±0.03µs        ? ?/sec
predicate_query_without_index/size_10000                     1.01    835.4±5.71µs        ? ?/sec    1.00    823.7±3.05µs        ? ?/sec
predicate_query_without_index/size_100000                    1.05     33.4±1.19ms        ? ?/sec    1.00     31.9±0.73ms        ? ?/sec
store_batch_insertion_without_predicates/size_100            1.00    158.3±0.43µs        ? ?/sec    1.00    157.8±1.23µs        ? ?/sec
store_batch_insertion_without_predicates/size_1000           1.00    963.9±4.59µs        ? ?/sec    1.01    969.1±4.42µs        ? ?/sec
store_batch_insertion_without_predicates/size_10000          1.00     10.8±0.06ms        ? ?/sec    1.00     10.9±0.03ms        ? ?/sec
store_batch_insertion_without_predicates/size_100000         1.00    108.7±1.02ms        ? ?/sec    1.00    109.1±1.19ms        ? ?/sec
store_retrieval_linear_cosine_similarity/size_100            1.00     16.9±0.05µs        ? ?/sec    1.00     17.0±0.03µs        ? ?/sec
store_retrieval_linear_cosine_similarity/size_1000           1.00    102.0±0.32µs        ? ?/sec    1.00    101.9±0.53µs        ? ?/sec
store_retrieval_linear_cosine_similarity/size_10000          1.00   1460.4±9.35µs        ? ?/sec    1.01   1478.4±7.92µs        ? ?/sec
store_retrieval_linear_cosine_similarity/size_100000         1.00     22.1±0.15ms        ? ?/sec    1.01     22.4±0.20ms        ? ?/sec
store_retrieval_linear_dot_product/size_100                  1.00     15.0±0.01µs        ? ?/sec    1.03     15.5±0.02µs        ? ?/sec
store_retrieval_linear_dot_product/size_1000                 1.00     97.5±0.39µs        ? ?/sec    1.00     97.0±0.37µs        ? ?/sec
store_retrieval_linear_dot_product/size_10000                1.00   1238.3±6.67µs        ? ?/sec    1.03   1272.4±9.94µs        ? ?/sec
store_retrieval_linear_dot_product/size_100000               1.00     20.6±0.15ms        ? ?/sec    1.00     20.6±0.33ms        ? ?/sec
store_retrieval_linear_euclidean_distance/size_100           1.00     15.2±0.04µs        ? ?/sec    1.05     15.9±0.01µs        ? ?/sec
store_retrieval_linear_euclidean_distance/size_1000          1.02     99.7±0.38µs        ? ?/sec    1.00     98.0±0.59µs        ? ?/sec
store_retrieval_linear_euclidean_distance/size_10000         1.01  1351.0±12.27µs        ? ?/sec    1.00   1334.8±6.23µs        ? ?/sec
store_retrieval_linear_euclidean_distance/size_100000        1.01     22.1±0.19ms        ? ?/sec    1.00     21.8±0.09ms        ? ?/sec
store_retrieval_no_condition/size_100                        1.00     17.0±0.01µs        ? ?/sec    1.00     17.0±0.02µs        ? ?/sec
store_retrieval_no_condition/size_1000                       1.00    102.6±0.47µs        ? ?/sec    1.00    102.3±0.56µs        ? ?/sec
store_retrieval_no_condition/size_10000                      1.00  1458.8±16.37µs        ? ?/sec    1.00  1457.6±11.14µs        ? ?/sec
store_retrieval_no_condition/size_100000                     1.00     22.9±0.23ms        ? ?/sec    1.01     23.0±0.06ms        ? ?/sec
store_retrieval_non_linear_hnsw/size_100                     1.02    125.1±0.27µs        ? ?/sec    1.00    122.9±0.15µs        ? ?/sec
store_retrieval_non_linear_hnsw/size_1000                    1.00    260.1±0.11µs        ? ?/sec    1.00    260.3±0.96µs        ? ?/sec
store_retrieval_non_linear_hnsw/size_10000                   1.00    397.9±0.13µs        ? ?/sec    1.14    453.7±4.10µs        ? ?/sec
store_retrieval_non_linear_hnsw/size_100000                  1.14    498.9±2.75µs        ? ?/sec    1.00    438.4±4.16µs        ? ?/sec
store_retrieval_non_linear_kdtree/size_100                   1.00    170.2±0.15µs        ? ?/sec    1.00    171.0±0.07µs        ? ?/sec
store_retrieval_non_linear_kdtree/size_1000                  1.00    964.2±2.94µs        ? ?/sec    1.00    967.2±0.58µs        ? ?/sec
store_retrieval_non_linear_kdtree/size_10000                 1.00     11.0±0.13ms        ? ?/sec    1.01     11.1±0.06ms        ? ?/sec
store_retrieval_non_linear_kdtree/size_100000                1.01    129.9±1.20ms        ? ?/sec    1.00    129.1±0.70ms        ? ?/sec
store_sequential_insertion_without_predicates/size_100       1.00    217.3±0.43µs        ? ?/sec    1.00    217.7±0.32µs        ? ?/sec
store_sequential_insertion_without_predicates/size_1000      1.00      2.2±0.00ms        ? ?/sec    1.00      2.2±0.00ms        ? ?/sec
store_sequential_insertion_without_predicates/size_10000     1.00     21.7±0.06ms        ? ?/sec    1.00     21.8±0.01ms        ? ?/sec
store_sequential_insertion_without_predicates/size_100000    1.00    218.5±0.57ms        ? ?/sec    1.00    219.1±0.07ms        ? ?/sec