Introduce OAL V2 engine

docs/en/changes/changes.md

@@ -1,6 +1,12 @@
 ## 10.4.0
 
 #### Project
+* Introduce OAL V2 engine:
+  - Immutable AST models for thread safety and predictable behavior
+  - Type-safe enums replacing string-based filter operators
+  - Precise error location reporting with file, line, and column numbers
+  - Clean separation between parsing and code generation phases
+  - Enhanced testability with models that can be constructed without parsing
 * Fix E2E test metrics verify: make it failure if the metric values all null.
 * Support building, testing, and publishing with Java 25.
 * Add `CLAUDE.md` as AI assistant guide for the project.

docs/en/concepts-and-designs/oal.md

@@ -174,7 +174,7 @@ endpoint_p99 = from(Endpoint.latency).filter(name in ("Endpoint1", "Endpoint2"))
 serv_Endpoint_p99 = from(Endpoint.latency).filter(name like "serv%").percentile2(10)
 
 // Calculate the avg response time of each Endpoint
-endpoint_resp_time = from(Endpoint.latency).avg()
+endpoint_resp_time = from(Endpoint.latency).longAvg()
 
 // Calculate the p50, p75, p90, p95 and p99 of each Endpoint by 50 ms steps.
 endpoint_percentile = from(Endpoint.latency).percentile2(10)