feat(engine): Vector index and SearchVectors contract for storage backends

.github/workflows/integration.yml

@@ -256,6 +256,14 @@ jobs:
           AWS_DEFAULT_REGION: us-east-1
           AWS_ACCESS_KEY_ID: ${{ steps.creds.outputs.akid }}
           AWS_SECRET_ACCESS_KEY: ${{ steps.creds.outputs.secret }}
+          # No in-tree backend implements vector search, so every vector request
+          # must be refused and the refusal suite must actually run. Without this
+          # the suite self-skips the moment a backend gains vector support, and the
+          # contract that non-participating backends refuse would stop being
+          # checked anywhere while still reporting green. Pinning the expectation
+          # turns that skip into a failure. The first backend to implement vector
+          # search sets this to 1 in its own job.
+          EXTENDDB_EXPECT_VECTORS: "0"
         run: |
           # Self-signed cert generated by init; trust it for the SDK client.
           export EXTENDDB_CA_CERT="$(grep -oP 'cert_path\s*=\s*"\K[^"]+' extenddb.toml)"

.gitignore

@@ -1,4 +1,5 @@
 /target
+/target-*
 extenddb.toml
 __pycache__/
 .coverage
@@ -19,3 +20,8 @@ extenddb.toml.bak
 .env
 .env.*
 !.env.example
+
+# Local test/dev config files
+extenddb-*.toml
+extenddb-*.toml.bak
+extenddb-*.toml.keep

crates/core/src/expression/mod.rs

@@ -17,6 +17,7 @@ mod parser_common;
 mod projection;
 mod reserved_words;
 mod resolver;
+mod search_condition;
 mod tokenizer;
 mod update_evaluator;
 mod update_parser;
@@ -33,6 +34,11 @@ pub use resolver::{
     resolve_name_ref, resolve_path, validate_begins_with_operands, validate_expression_param_usage,
     validate_ordering_operand_types, validate_unused_attributes,
 };
+pub use search_condition::{
+    MAX_INLINE_FILTER_CONDITIONS, MAX_PARTITION_KEY_CONDITIONS, MAX_SEARCH_CONDITIONS,
+    SearchCondition, validate_conditions_against_search_schema,
+    validate_search_condition_expression,
+};
 pub use tokenizer::{Token, tokenize, tokenize_for, tokenize_with_limit};
 pub use update_evaluator::apply_update;
 pub use update_parser::{parse_update, parse_update_from};