Track resource-backed skill invocations (#38066)

## What changed

- Emit skill invocation analytics when a resource-backed skill is explicitly selected or its main resource is successfully read from the first page.
- Preserve provider-supplied skill IDs and user scope when available, and derive a stable ID from the main resource otherwise.
- Deduplicate repeated implicit reads of the same main resource within a turn.

## Testing

- Extend the orchestrator skill integration test to cover explicit and implicit invocation events, stable fallback IDs, failed reads, and repeated-read deduplication.

GitOrigin-RevId: 7d8453b31b5a2205847e65cda2c46183d6c97b45

codex-rs/core/src/session/session.rs

@@ -1186,6 +1186,7 @@ impl Session {
             ));
             let session_extension_data =
                 codex_extension_api::ExtensionData::new(session_id.to_string());
+            session_extension_data.insert(analytics_events_client.clone());
             let mcp_resource_client = Arc::new(McpResourceClient::new(Arc::clone(&mcp_runtime)));
             let extension_metrics =
                 extension_metrics::from_session_telemetry(session_telemetry.clone());