[plugins] Track plugin install requests by ID (#29684)

Summary
- Emit `codex_plugin_install_requested` when a validated plugin install
request is made, before the user accepts or declines the elicitation.
- Record the exact model-visible plugin ID, remote plugin ID, required
connector IDs, stable suggestion ID, and `endpoint_recommendation` vs
`legacy_discovery` source.
- Keep `suggest_reason` out of telemetry and leave connector-only
install requests unchanged.

Rollout
- Backend/schema dependency:
https://github.com/openai/openai/pull/1065270
- Land the backend PR before this producer starts sending the event.

Validation
- `just test -p codex-analytics` (83 passed)
- `just test -p codex-core request_plugin_install` (17 passed)
- `just fix -p codex-analytics`
- `just fix -p codex-core`
- `just fmt`
- `git diff --check`

codex-rs/analytics/src/analytics_client_tests.rs

@@ -62,6 +62,10 @@ use crate::facts::HookRunInput;
 use crate::facts::InputError;
 use crate::facts::InvocationType;
 use crate::facts::PluginInstallFailedInput;
+use crate::facts::PluginInstallRequestSource;
+use crate::facts::PluginInstallRequested;
+use crate::facts::PluginInstallRequestedInput;
+use crate::facts::PluginInstallRequestedPlugin;
 use crate::facts::PluginState;
 use crate::facts::PluginStateChangedInput;
 use crate::facts::PluginUsedInput;
@@ -3447,6 +3451,66 @@ async fn reducer_ingests_plugin_state_changed_fact() {
     );
 }
 
+#[tokio::test]
+async fn reducer_ingests_plugin_install_requested_fact() {
+    let mut reducer = AnalyticsReducer::default();
+    let mut events = Vec::new();
+    let tracking = test_tracking_context("thread-1", "turn-1");
+    let request = PluginInstallRequested {
+        suggestion_id: "request_plugin_install_call-1".to_string(),
+        plugins: vec![
+            PluginInstallRequestedPlugin {
+                plugin_id: "calendar@openai-curated-remote".to_string(),
+                remote_plugin_id: Some("plugin_calendar".to_string()),
+                plugin_name: "Calendar".to_string(),
+                connector_ids: vec!["connector_calendar".to_string()],
+            },
+            PluginInstallRequestedPlugin {
+                plugin_id: "github@openai-curated-remote".to_string(),
+                remote_plugin_id: None,
+                plugin_name: "GitHub".to_string(),
+                connector_ids: vec!["connector_github".to_string()],
+            },
+        ],
+        source: PluginInstallRequestSource::EndpointRecommendation,
+    };
+
+    reducer
+        .ingest(
+            AnalyticsFact::Custom(CustomAnalyticsFact::PluginInstallRequested(
+                PluginInstallRequestedInput { tracking, request },
+            )),
+            &mut events,
+        )
+        .await;
+
+    assert_eq!(
+        serde_json::to_value(&events).expect("serialize events"),
+        json!([{
+            "event_type": "codex_plugin_install_requested",
+            "event_params": {
+                "suggestion_id": "request_plugin_install_call-1",
+                "plugins": [{
+                    "plugin_id": "calendar@openai-curated-remote",
+                    "remote_plugin_id": "plugin_calendar",
+                    "plugin_name": "Calendar",
+                    "connector_ids": ["connector_calendar"],
+                }, {
+                    "plugin_id": "github@openai-curated-remote",
+                    "remote_plugin_id": null,
+                    "plugin_name": "GitHub",
+                    "connector_ids": ["connector_github"],
+                }],
+                "source": "endpoint_recommendation",
+                "thread_id": "thread-1",
+                "turn_id": "turn-1",
+                "model_slug": "gpt-5",
+                "product_client_id": originator().value,
+            }
+        }])
+    );
+}
+
 #[tokio::test]
 async fn reducer_ingests_plugin_install_failed_fact() {
     let mut reducer = AnalyticsReducer::default();