[codex] Dedupe plugin MCPs by app declaration name (#27607)

## Context

This is the next step in the plugin auth-routing stack. The earlier PRs
make `PluginsManager` auth-aware and move the broad App/MCP surface
decision into that layer. This PR narrows the ChatGPT/SIWC behavior so
we only hide a plugin MCP server when it conflicts with an App
declaration of the same name.

In product terms: if a plugin exposes both an App route and MCP route
for `foo`, ChatGPT/SIWC sessions should use the App route for `foo`. If
the same plugin also exposes a separate MCP server like `foo2`, that MCP
server should remain available.

```json
// .app.json
{
  "apps": {
    "foo": {
      "id": "connector_abc"
    }
  }
}
```

```json
// .mcp.json
{
  "mcpServers": {
    "foo": {
      "url": "https://mcp.foo.com/mcp"
    },
    "foo2": {
      "url": "https://mcp.foo2.com/mcp"
    }
  }
}
```

## Stack

- PR1: #27652 seed plugin manager auth at construction.
- PR2: #27459 route plugin surfaces by auth mode.
- PR3: #27607 dedupe plugin MCP servers by App declaration name.
- PR4: #27602 preserve plugin Apps in connector listings.
- PR5: #27461 skip install-time plugin MCP OAuth for matching App
routes.

## Summary

- Preserve App declaration names in loaded plugin metadata.
- Keep public effective App outputs as deduped connector IDs for
existing callers.
- For ChatGPT/SIWC, suppress only plugin MCP servers whose names match
declared App names.

## Validation

```bash
cargo fmt --all
cargo test -p codex-core-plugins plugin_auth_projection
cargo test -p codex-core-plugins effective_apps
cargo test -p codex-core-plugins read_plugin_for_config_installed_git_source_reads_from_cache_without_cloning
cargo test -p codex-core explicit_plugin_mentions_use_apps_for_chatgpt_dual_surface_plugins
cargo test -p codex-core explicit_plugin_mentions_keep_non_conflicting_mcp_for_chatgpt_auth
cargo test -p codex-app-server --test all plugin_install_filters_disallowed_apps_needing_auth
git diff --check
```

---------

Co-authored-by: Xin Lin <xl@openai.com>

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

@@ -25,6 +25,7 @@ use codex_exec_server::LOCAL_FS;
 use codex_mcp::PluginMcpServerPlacement;
 use codex_mcp::parse_plugin_mcp_config;
 use codex_plugin::AppConnectorId;
+use codex_plugin::AppDeclaration;
 use codex_plugin::LoadedPlugin;
 use codex_plugin::PluginCapabilitySummary;
 use codex_plugin::PluginHookSource;
@@ -32,6 +33,7 @@ use codex_plugin::PluginId;
 use codex_plugin::PluginIdError;
 use codex_plugin::PluginLoadOutcome;
 use codex_plugin::PluginTelemetryMetadata;
+use codex_plugin::app_connector_ids_from_declarations;
 use codex_protocol::protocol::Product;
 use codex_protocol::protocol::SkillScope;
 use codex_utils_absolute_path::AbsolutePathBuf;
@@ -63,12 +65,6 @@ pub struct PluginHookLoadOutcome {
     pub hook_load_warnings: Vec<String>,
 }
 
-#[derive(Debug, Clone, PartialEq, Eq)]
-pub struct PluginAppMetadata {
-    pub id: AppConnectorId,
-    pub category: Option<String>,
-}
-
 enum PluginLoadScope<'a> {
     AllCapabilities {
         restriction_product: Option<Product>,
@@ -835,15 +831,7 @@ fn default_mcp_config_paths(plugin_root: &Path) -> Vec<AbsolutePathBuf> {
     paths
 }
 
-pub async fn load_plugin_apps(plugin_root: &Path) -> Vec<AppConnectorId> {
-    load_plugin_app_metadata(plugin_root)
-        .await
-        .into_iter()
-        .map(|app| app.id)
-        .collect()
-}
-
-pub async fn load_plugin_app_metadata(plugin_root: &Path) -> Vec<PluginAppMetadata> {
+pub async fn load_plugin_apps(plugin_root: &Path) -> Vec<AppDeclaration> {
     if let Some(manifest) = load_plugin_manifest(plugin_root) {
         return load_apps_from_paths(
             plugin_root,
@@ -854,13 +842,13 @@ pub async fn load_plugin_app_metadata(plugin_root: &Path) -> Vec<PluginAppMetada
     load_apps_from_paths(plugin_root, default_app_config_paths(plugin_root)).await
 }
 
-pub fn plugin_app_metadata_from_value(value: &JsonValue) -> Vec<PluginAppMetadata> {
+pub fn plugin_app_declarations_from_value(value: &JsonValue) -> Vec<AppDeclaration> {
     let Ok(parsed) = serde_json::from_value::<PluginAppFile>(value.clone()) else {
         return Vec::new();
     };
-    let mut apps = plugin_app_metadata_from_file(parsed, /*plugin_root*/ None);
+    let mut apps = app_declarations_from_file(parsed, /*plugin_root*/ None);
     let mut seen_connector_ids = HashSet::new();
-    apps.retain(|app| seen_connector_ids.insert(app.id.0.clone()));
+    apps.retain(|app| seen_connector_ids.insert(app.connector_id.0.clone()));
     apps
 }
 
@@ -1000,8 +988,8 @@ fn append_plugin_hook_file(
 async fn load_apps_from_paths(
     plugin_root: &Path,
     app_config_paths: Vec<AbsolutePathBuf>,
-) -> Vec<PluginAppMetadata> {
-    let mut apps = Vec::new();
+) -> Vec<AppDeclaration> {
+    let mut app_declarations = Vec::new();
     for app_config_path in app_config_paths {
         let Ok(contents) = tokio::fs::read_to_string(app_config_path.as_path()).await else {
             continue;
@@ -1017,21 +1005,19 @@ async fn load_apps_from_paths(
             }
         };
 
-        apps.extend(plugin_app_metadata_from_file(parsed, Some(plugin_root)));
+        app_declarations.extend(app_declarations_from_file(parsed, Some(plugin_root)));
     }
-    let mut seen_connector_ids = HashSet::new();
-    apps.retain(|app| seen_connector_ids.insert(app.id.0.clone()));
-    apps
+    app_declarations
 }
 
-fn plugin_app_metadata_from_file(
+fn app_declarations_from_file(
     parsed: PluginAppFile,
     plugin_root: Option<&Path>,
-) -> Vec<PluginAppMetadata> {
+) -> Vec<AppDeclaration> {
     parsed
         .apps
-        .into_values()
-        .filter_map(|app| {
+        .into_iter()
+        .filter_map(|(name, app)| {
             if app.id.trim().is_empty() {
                 if let Some(plugin_root) = plugin_root {
                     warn!(
@@ -1041,18 +1027,22 @@ fn plugin_app_metadata_from_file(
                 }
                 None
             } else {
-                Some(PluginAppMetadata {
-                    id: AppConnectorId(app.id),
-                    category: app
-                        .category
-                        .map(|category| category.trim().to_string())
-                        .filter(|category| !category.is_empty()),
+                Some(AppDeclaration {
+                    name,
+                    connector_id: AppConnectorId(app.id),
+                    category: cleaned_app_category(app.category),
                 })
             }
         })
         .collect()
 }
 
+fn cleaned_app_category(category: Option<String>) -> Option<String> {
+    category
+        .map(|category| category.trim().to_string())
+        .filter(|category| !category.is_empty())
+}
+
 pub async fn plugin_telemetry_metadata_from_root(
     plugin_id: &PluginId,
     plugin_root: &AbsolutePathBuf,
@@ -1075,6 +1065,13 @@ pub async fn plugin_telemetry_metadata_from_root(
     mcp_server_names.sort_unstable();
     mcp_server_names.dedup();
 
+    let app_declarations = load_apps_from_paths(
+        plugin_root.as_path(),
+        plugin_app_config_paths(plugin_root.as_path(), manifest_paths),
+    )
+    .await;
+    let app_connector_ids = app_connector_ids_from_declarations(&app_declarations);
+
     PluginTelemetryMetadata {
         plugin_id: plugin_id.clone(),
         remote_plugin_id: None,
@@ -1084,14 +1081,7 @@ pub async fn plugin_telemetry_metadata_from_root(
             description: None,
             has_skills,
             mcp_server_names,
-            app_connector_ids: load_apps_from_paths(
-                plugin_root.as_path(),
-                plugin_app_config_paths(plugin_root.as_path(), manifest_paths),
-            )
-            .await
-            .into_iter()
-            .map(|app| app.id)
-            .collect(),
+            app_connector_ids,
         }),
     }
 }