[codex-analytics] feature plumbing and emittance (#16640)

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[//]: # (BEGIN SAPLING FOOTER)
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with [ReviewStack](https://reviewstack.dev/openai/codex/pull/16640).
* #16870
* #16706
* #16641
* __->__ #16640

codex-rs/core/src/tasks/mod.rs

@@ -30,6 +30,7 @@ use crate::hook_runtime::record_pending_input;
 use crate::state::ActiveTurn;
 use crate::state::RunningTask;
 use crate::state::TaskKind;
+use codex_analytics::TurnTokenUsageFact;
 use codex_login::AuthManager;
 use codex_models_manager::manager::ModelsManager;
 use codex_otel::SessionTelemetry;
@@ -497,6 +498,13 @@ impl Session {
                     - token_usage_at_turn_start.total_tokens)
                     .max(0),
             };
+            self.services
+                .analytics_events_client
+                .track_turn_token_usage(TurnTokenUsageFact {
+                    turn_id: turn_context.sub_id.clone(),
+                    thread_id: self.conversation_id.to_string(),
+                    token_usage: turn_token_usage.clone(),
+                });
             self.services.session_telemetry.histogram(
                 TURN_TOKEN_USAGE_METRIC,
                 turn_token_usage.total_tokens,