[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/events.rs

@@ -14,6 +14,7 @@ use crate::facts::CompactionTrigger;
 use crate::facts::GoalEventKind;
 use crate::facts::HookRunFact;
 use crate::facts::InvocationType;
+use crate::facts::PluginInstallRequested;
 use crate::facts::PluginState;
 use crate::facts::SubAgentThreadStartedInput;
 use crate::facts::ThreadInitializationMode;
@@ -80,6 +81,7 @@ pub(crate) enum TrackEventRequest {
     #[allow(dead_code)]
     ReviewEvent(CodexReviewEventRequest),
     PluginUsed(CodexPluginUsedEventRequest),
+    PluginInstallRequested(CodexPluginInstallRequestedEventRequest),
     PluginInstalled(CodexPluginEventRequest),
     PluginUninstalled(CodexPluginEventRequest),
     PluginEnabled(CodexPluginEventRequest),
@@ -954,6 +956,31 @@ pub(crate) struct CodexPluginUsedMetadata {
     pub(crate) model_slug: Option<String>,
 }
 
+#[derive(Serialize)]
+pub(crate) struct CodexPluginInstallRequestedPluginMetadata {
+    pub(crate) plugin_id: String,
+    pub(crate) remote_plugin_id: Option<String>,
+    pub(crate) plugin_name: String,
+    pub(crate) connector_ids: Vec<String>,
+}
+
+#[derive(Serialize)]
+pub(crate) struct CodexPluginInstallRequestedMetadata {
+    pub(crate) suggestion_id: String,
+    pub(crate) plugins: Vec<CodexPluginInstallRequestedPluginMetadata>,
+    pub(crate) source: crate::facts::PluginInstallRequestSource,
+    pub(crate) thread_id: String,
+    pub(crate) turn_id: String,
+    pub(crate) model_slug: String,
+    pub(crate) product_client_id: Option<String>,
+}
+
+#[derive(Serialize)]
+pub(crate) struct CodexPluginInstallRequestedEventRequest {
+    pub(crate) event_type: &'static str,
+    pub(crate) event_params: CodexPluginInstallRequestedMetadata,
+}
+
 #[derive(Serialize)]
 pub(crate) struct CodexPluginEventRequest {
     pub(crate) event_type: &'static str,
@@ -1074,6 +1101,30 @@ fn codex_plugin_metadata_with_product_client_id(
     }
 }
 
+pub(crate) fn codex_plugin_install_requested_metadata(
+    tracking: &TrackEventsContext,
+    request: PluginInstallRequested,
+) -> CodexPluginInstallRequestedMetadata {
+    CodexPluginInstallRequestedMetadata {
+        suggestion_id: request.suggestion_id,
+        plugins: request
+            .plugins
+            .into_iter()
+            .map(|plugin| CodexPluginInstallRequestedPluginMetadata {
+                plugin_id: plugin.plugin_id,
+                remote_plugin_id: plugin.remote_plugin_id,
+                plugin_name: plugin.plugin_name,
+                connector_ids: plugin.connector_ids,
+            })
+            .collect(),
+        source: request.source,
+        thread_id: tracking.thread_id.clone(),
+        turn_id: tracking.turn_id.clone(),
+        model_slug: tracking.model_slug.clone(),
+        product_client_id: Some(originator().value),
+    }
+}
+
 pub(crate) fn codex_compaction_event_params(
     input: CodexCompactionEvent,
     session_id: String,