[codex] Centralize Plugin Analytics Metadata (#27102)

This PR moves construction of `PluginTelemetryMetadata` from loader and
model helpers into `PluginsManager`, which already owns installed plugin
state and will eventually perform remote identity enrichment. The
metadata type remains in `codex-plugin`, and serialized analytics events
remain unchanged.

## Before

```mermaid
flowchart LR
    subgraph Events["Analytics event paths"]
        direction TB
        Lifecycle["Local install / uninstall"]
        Config["Enable / disable"]
        Remote["Remote install"]
        Used["Plugin used"]
    end

    subgraph Construction["Metadata construction"]
        direction TB
        Loader["Loader telemetry helpers"]
        Summary["PluginCapabilitySummary::telemetry_metadata"]
        Override["Caller adds remote_plugin_id"]
    end

    Metadata["PluginTelemetryMetadata"]

    Lifecycle --> Loader
    Config --> Loader
    Remote --> Loader
    Loader -->|"local events"| Metadata
    Loader -->|"remote install"| Override
    Override --> Metadata
    Used --> Summary
    Summary --> Metadata
```

Telemetry metadata was constructed through loader helpers, a
capability-summary method, and a remote-install call-site override.

## After

```mermaid
flowchart LR
    subgraph Events["Analytics event paths"]
        direction TB
        Lifecycle["Local install / uninstall"]
        Config["Enable / disable"]
        Remote["Remote install"]
        Used["Plugin used"]
    end

    Manager["PluginsManager — single construction owner"]
    Metadata["PluginTelemetryMetadata"]

    Lifecycle --> Manager
    Config --> Manager
    Remote -->|"authoritative remote ID"| Manager
    Used -->|"capability summary"| Manager
    Manager --> Metadata
```

Every analytics path delegates metadata construction to
`PluginsManager`. Remote install still supplies its authoritative
backend ID explicitly.

## What Changes

- Make loader code return a focused plugin capability summary instead of
constructing analytics metadata.
- Centralize immutable plugin telemetry metadata construction in
`PluginsManager`.
- Route local install/uninstall, remote install, enable/disable, and
plugin-used emitters through the manager.
- Preserve the current serialized analytics contract exactly.

Normal metadata still has no remote override. Remote install continues
to provide its authoritative backend ID explicitly, so the existing
serializer continues reporting that ID through `plugin_id`.
Snapshot-based enrichment is intentionally deferred to the final PR.

## Testing

- `just test -p codex-core-plugins` (238 tests passed)
- `just test -p codex-plugin` (3 tests passed)
- Scoped Clippy/compile checks passed for `codex-plugin`,
`codex-core-plugins`, `codex-app-server`, and `codex-core`.

## Split Overview

```text
main
├── #27093  Debug analytics capture                 (merged)
├── #27099  Non-mutating plugin smoke               (merged)
├── #27100  Remote install/uninstall smoke          (merged)
└── #27102  Plugin telemetry metadata refactor      ← you are here
    └── #27669  Persist remote plugin identity

After #27102 and #27669 merge:
└── Final PR: add explicit local and remote IDs to plugin analytics
```

Review order and dependencies:

1. [#27093 Add debug-only analytics event
capture](https://github.com/openai/codex/pull/27093) (merged)
2. [#27099 Add a plugin analytics smoke
workflow](https://github.com/openai/codex/pull/27099) (merged)
3. [#27100 Add a remote plugin analytics mutation smoke
workflow](https://github.com/openai/codex/pull/27100) (merged)
4. This metadata refactor, independent and based on `main`
5. [#27669 Persist remote plugin
identity](https://github.com/openai/codex/pull/27669), stacked on this
PR
6. Final remote-ID behavior PR, created after the prerequisites merge

The original [#26281](https://github.com/openai/codex/pull/26281)
remains open as the aggregate reference until the final replacement PR
is published.

codex-rs/core-plugins/src/loader.rs

@@ -38,7 +38,6 @@ use codex_plugin::PluginCapabilitySummary;
 use codex_plugin::PluginHookSource;
 use codex_plugin::PluginId;
 use codex_plugin::PluginIdError;
-use codex_plugin::PluginTelemetryMetadata;
 use codex_plugin::app_connector_ids_from_declarations;
 use codex_protocol::protocol::Product;
 use codex_protocol::protocol::SkillScope;
@@ -1164,13 +1163,11 @@ fn cleaned_app_category(category: Option<String>) -> Option<String> {
         .filter(|category| !category.is_empty())
 }
 
-pub async fn plugin_telemetry_metadata_from_root(
+pub async fn plugin_capability_summary_from_root(
     plugin_id: &PluginId,
     plugin_root: &AbsolutePathBuf,
-) -> PluginTelemetryMetadata {
-    let Some(manifest) = load_plugin_manifest(plugin_root.as_path()) else {
-        return PluginTelemetryMetadata::from_plugin_id(plugin_id);
-    };
+) -> Option<PluginCapabilitySummary> {
+    let manifest = load_plugin_manifest(plugin_root.as_path())?;
 
     let manifest_paths = &manifest.paths;
     let has_skills = !plugin_skill_roots(plugin_root, manifest_paths).is_empty();
@@ -1192,18 +1189,14 @@ pub async fn plugin_telemetry_metadata_from_root(
     .await;
     let app_connector_ids = app_connector_ids_from_declarations(&app_declarations);
 
-    PluginTelemetryMetadata {
-        plugin_id: plugin_id.clone(),
-        remote_plugin_id: None,
-        capability_summary: Some(PluginCapabilitySummary {
-            config_name: plugin_id.as_key(),
-            display_name: plugin_id.plugin_name.clone(),
-            description: None,
-            has_skills,
-            mcp_server_names,
-            app_connector_ids,
-        }),
-    }
+    Some(PluginCapabilitySummary {
+        config_name: plugin_id.as_key(),
+        display_name: plugin_id.plugin_name.clone(),
+        description: None,
+        has_skills,
+        mcp_server_names,
+        app_connector_ids,
+    })
 }
 
 pub async fn load_plugin_mcp_servers(
@@ -1279,24 +1272,6 @@ pub(crate) async fn load_plugin_mcp_servers_from_manifest(
     mcp_servers
 }
 
-pub async fn installed_plugin_telemetry_metadata(
-    codex_home: &Path,
-    plugin_id: &PluginId,
-) -> PluginTelemetryMetadata {
-    let store = match PluginStore::try_new(codex_home.to_path_buf()) {
-        Ok(store) => store,
-        Err(err) => {
-            warn!("failed to resolve plugin cache root: {err}");
-            return PluginTelemetryMetadata::from_plugin_id(plugin_id);
-        }
-    };
-    let Some(plugin_root) = store.active_plugin_root(plugin_id) else {
-        return PluginTelemetryMetadata::from_plugin_id(plugin_id);
-    };
-
-    plugin_telemetry_metadata_from_root(plugin_id, &plugin_root).await
-}
-
 async fn load_mcp_servers_from_file(
     plugin_root: &Path,
     mcp_config_path: &AbsolutePathBuf,