Expose plugin manifest keywords in app server (#21271)

## Summary
- Add plugin manifest keywords to core plugin marketplace/detail models
- Expose keywords on app-server v2 PluginSummary and generated
schema/types
- Populate keywords in plugin/list and plugin/read responses for local
plugins

Depends on https://github.com/openai/openai/pull/891087

## Validation
- just fmt
- just write-app-server-schema
- cargo test -p codex-app-server-protocol
- cargo test -p codex-core-plugins
- cargo test -p codex-app-server
plugin_list_keeps_valid_marketplaces_when_another_marketplace_fails_to_load
- cargo test -p codex-app-server
plugin_read_returns_plugin_details_with_bundle_contents

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

@@ -62,6 +62,7 @@ pub struct MarketplacePlugin {
     pub source: MarketplacePluginSource,
     pub policy: MarketplacePluginPolicy,
     pub interface: Option<PluginManifestInterface>,
+    pub keywords: Vec<String>,
 }
 
 #[derive(Debug, Clone, PartialEq, Eq)]
@@ -293,6 +294,10 @@ pub fn load_marketplace(path: &AbsolutePathBuf) -> Result<Marketplace, Marketpla
             source: plugin.source,
             policy: plugin.policy,
             interface: plugin.interface,
+            keywords: plugin
+                .manifest
+                .map(|manifest| manifest.keywords)
+                .unwrap_or_default(),
         });
     }