feat: add extensible LLM optimization accounting

crates/adaptive/tests/coverage/subscriber_tests.rs

@@ -133,6 +133,7 @@ fn test_event_to_call_record_llm_end_with_annotated_response_stays_observability
                     finish_reason: Some(FinishReason::Complete),
                     usage: None,
                     api_specific: None,
+                    optimization_summary: None,
                     extra: serde_json::Map::new(),
                 }))
                 .build(),

crates/adaptive/tests/unit/drain_tests.rs

@@ -873,6 +873,7 @@ fn test_accumulator_extracts_annotated_response() {
             cost: None,
         }),
         api_specific: None,
+        optimization_summary: None,
         extra: serde_json::Map::new(),
     };
 
@@ -990,6 +991,7 @@ fn test_accumulator_annotated_response_partial_data() {
         finish_reason: None,
         usage: None,
         api_specific: None,
+        optimization_summary: None,
         extra: serde_json::Map::new(),
     };
 

crates/core/src/api/mod.rs

@@ -7,6 +7,8 @@
 pub mod event;
 /// LLM lifecycle helpers and managed execution entry points.
 pub mod llm;
+/// Plugin-neutral evidence recording for managed LLM calls.
+pub mod optimization;
 /// Global and scope-local middleware registration helpers.
 pub mod registry;
 /// Advanced runtime state, callbacks, and scope-stack helpers.