Measure Guardian approval blocking time per turn (#55591)

## What changed

Record `codex.guardian.turn.blocking_ms` when a turn completes or aborts, with an `outcome` label. Count overlapping approval waits once, exclude idle gaps, and split pending reviews across the active turns they span. Use each turn's telemetry so samples retain the servicing turn's model attribution.

## Testing

Add unit coverage for overlapping waits, idle gaps, late turn completion, and duplicate stops. Extend integration coverage to verify attribution across turns and model changes for yielded command reviews and MCP elicitation, including aborted turns.

GitOrigin-RevId: a3e6a0c32a06fe58ea93119ecd941076100fb82c

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

@@ -21,6 +21,9 @@ impl Session {
     ) {
         let metadata: Arc<dyn TurnAnalyticsMetadata> = turn_context.turn_metadata_state.clone();
         turn_context.extension_data.insert(metadata);
+        turn_context
+            .extension_data
+            .insert(turn_context.session_telemetry.clone());
         let collaboration_mode = turn_context.collaboration_mode();
         for contributor in self.services.extensions.turn_lifecycle_contributors() {
             if contributor.turn_start_phase(&self.services.thread_extension_data) != phase {