Refactor usage body capture and stream terminal reporting

apps/aether-gateway/src/ai_pipeline/adaptation/mod.rs

@@ -14,4 +14,5 @@ pub(crate) use private_envelope::{
     maybe_normalize_provider_private_sync_report_payload,
     normalize_provider_private_report_context, normalize_provider_private_response_value,
     provider_private_response_allows_sync_finalize, transform_provider_private_stream_line,
+    ProviderPrivateStreamNormalizer,
 };

apps/aether-gateway/src/ai_pipeline/mod.rs

@@ -14,7 +14,9 @@ use crate::{usage::GatewaySyncReportRequest, AppState, GatewayError};
 
 use self::contracts::ExecutionRuntimeAuthContext;
 
-pub(crate) use self::adaptation::maybe_build_provider_private_stream_normalizer;
+pub(crate) use self::adaptation::{
+    maybe_build_provider_private_stream_normalizer, ProviderPrivateStreamNormalizer,
+};
 pub(crate) use self::finalize::common::LocalCoreSyncFinalizeOutcome;
 pub(crate) use self::finalize::internal::{
     maybe_build_stream_response_rewriter, maybe_build_sync_finalize_outcome,