Add metrics for extension-rendered skill catalogs (#35597)

## What changed

- Add an optional `ExtensionMetrics` capability to thread, turn-input, and world-state contributors, backed by session telemetry in the host.
- Record skill counts, omissions, and truncated description characters for extension-rendered catalogs, tagged by the catalog surface.
- Preserve host session attribution on extension metrics, including the effective model for each turn, and prevent extension tags from overriding host metadata.
- Avoid duplicate host-catalog samples by recording world-state metrics only when the section is published or changes.

## Testing

- Cover metric values and surface tags, session metadata preservation, turn-level model changes, and host world-state publication behavior.

GitOrigin-RevId: 9059e521943a8f81df25a38b03692eddbc1d990d

codex-rs/ext/extension-api/src/contributors.rs

@@ -10,6 +10,7 @@ use codex_tools::ToolCall;
 use codex_tools::ToolExecutor;
 
 use crate::ExtensionData;
+use crate::ExtensionMetrics;
 
 mod context;
 mod mcp;
@@ -205,10 +206,12 @@ pub trait TurnLifecycleContributor: Send + Sync {
 /// host-specific dependencies belong on the extension value installed by the
 /// host, not in this input.
 pub trait TurnInputContributor: Send + Sync {
-    /// Returns additional contextual fragments for one submitted turn.
+    /// Returns additional contextual fragments for one submitted turn. The optional metrics
+    /// capability is bound to the effective model for that turn.
     fn contribute<'a>(
         &'a self,
         input: TurnInputContext,
+        extension_metrics: Option<Arc<dyn ExtensionMetrics>>,
         session_store: &'a ExtensionData,
         thread_store: &'a ExtensionData,
         turn_store: &'a ExtensionData,