Separate local and remote plugin analytics IDs (#29495)

## Why

Plugin analytics overloaded `plugin_id`: most events used the Codex
`<plugin>@<marketplace>` identity, while remote install events used the
backend plugin ID. That makes the same field change meaning across event
types and complicates downstream identity resolution.

This change makes the contract unambiguous:

- `plugin_id`: the local Codex `<plugin>@<marketplace>` identity, when
resolved
- `remote_plugin_id`: the backend plugin identity, when available

For a remote install failure that happens before plugin details resolve,
`plugin_id` is `null` and `remote_plugin_id` remains populated.

## What changed

All six plugin analytics events use the same identity contract:

- `codex_plugin_installed`
- `codex_plugin_install_failed`
- `codex_plugin_uninstalled`
- `codex_plugin_enabled`
- `codex_plugin_disabled`
- `codex_plugin_used`

Remote identity is resolved from the current installed-plugin snapshot
first, with persisted install metadata as fallback. The telemetry
metadata type keeps local identity optional for failures that occur
before remote details are available.

The app-server test client's manual analytics smokes now find remote
mutation events through `remote_plugin_id` and validate that `plugin_id`
remains local.

## Remote uninstall

Resolve and capture telemetry metadata before removing the local plugin
cache, then emit `codex_plugin_uninstalled` after the backend confirms
success. The event is also emitted when backend uninstall succeeds but
local cache cleanup reports `CacheRemove`.

If a concurrent remote-cache refresh removes the local bundle before
telemetry capture, the already-fetched remote plugin detail supplies
fallback capability metadata.

## Validation

- `just test -p codex-analytics` — 82 passed
- `just test -p codex-core-plugins` — 271 passed
- `just test -p codex-app-server-test-client` — 5 passed
- `just test -p codex-plugin` — 3 passed
- `just test -p codex-app-server plugin_install` — 37 passed
- `just test -p codex-app-server plugin_uninstall` — 10 passed

The production app-server install/uninstall flow was also exercised
against `plugins~Plugin_f1b845ac33888191ac156169c58733c2`
(`build-ios-apps@openai-curated-remote`), and the plugin's original
uninstalled state was restored.

codex-rs/app-server-test-client/src/plugin_analytics_smoke.rs

@@ -159,6 +159,7 @@ fn wait_for_plugin_usage(
 #[derive(Debug)]
 struct ExpectedPlugin {
     plugin_id: String,
+    remote_plugin_id: String,
     plugin_name: String,
     marketplace_name: String,
 }
@@ -208,13 +209,15 @@ fn expected_plugin(response: &PluginInstalledResponse, plugin_id: &str) -> Resul
             plugin.availability
         );
     }
-    plugin
+    let remote_plugin_id = plugin
         .remote_plugin_id
         .as_ref()
-        .with_context(|| format!("plugin `{plugin_id}` does not have a remote plugin id"))?;
+        .with_context(|| format!("plugin `{plugin_id}` does not have a remote plugin id"))?
+        .clone();
 
     Ok(ExpectedPlugin {
         plugin_id: plugin.id.clone(),
+        remote_plugin_id,
         plugin_name: plugin.name.clone(),
         marketplace_name: marketplace.name.clone(),
     })
@@ -444,6 +447,7 @@ fn event_count(events: &[Value], event_type: &str) -> usize {
 fn validate_identity(event: &Value, expected: &ExpectedPlugin) -> Result<()> {
     let params = &event["event_params"];
     require_string(params, "plugin_id", &expected.plugin_id)?;
+    require_string(params, "remote_plugin_id", &expected.remote_plugin_id)?;
     require_string(params, "plugin_name", &expected.plugin_name)?;
     require_string(params, "marketplace_name", &expected.marketplace_name)
 }