Propagate remote plugin IDs to skill metadata (#35261)

## What changed

- Carry a plugin's local and remote identities together from plugin loading into
  `SkillMetadata`.
- Resolve remote IDs from the installed-plugin snapshot when available, falling
  back to persisted install metadata only when no snapshot exists.
- Include plugin identity in skill cache keys so identity changes refresh cached
  skill metadata.

## Testing

- Cover snapshot and persisted identity resolution, local marketplace isolation,
  cached skill refreshes, and propagation through plugin skill snapshots.

GitOrigin-RevId: aabeeb631a43361fe817358ace7f1ea8ba5db708

codex-rs/plugin/src/load_outcome.rs

@@ -2,6 +2,7 @@ use std::collections::HashMap;
 use std::collections::HashSet;
 
 use codex_utils_absolute_path::AbsolutePathBuf;
+use codex_utils_plugins::PluginIdentity;
 use codex_utils_plugins::PluginSkillRoot;
 use codex_utils_plugins::SkillDiscoveryMode;
 
@@ -17,6 +18,7 @@ const MAX_CAPABILITY_SUMMARY_DESCRIPTION_LEN: usize = 1024;
 #[derive(Debug, Clone, PartialEq)]
 pub struct LoadedPlugin<M> {
     pub config_name: String,
+    pub remote_plugin_id: Option<String>,
     pub manifest_name: Option<String>,
     pub plugin_namespace: Option<String>,
     pub manifest_description: Option<String>,
@@ -135,7 +137,10 @@ impl<M: Clone> PluginLoadOutcome<M> {
                 if seen_paths.insert(path.clone()) {
                     skill_roots.push(PluginSkillRoot {
                         path: path.clone(),
-                        plugin_id: plugin.config_name.clone(),
+                        plugin_identity: PluginIdentity {
+                            plugin_id: plugin.config_name.clone(),
+                            remote_plugin_id: plugin.remote_plugin_id.clone(),
+                        },
                         plugin_namespace: plugin_namespace.clone(),
                         plugin_root: plugin.root.clone(),
                         discovery_mode: SkillDiscoveryMode::Recursive,
@@ -224,6 +229,7 @@ mod tests {
     fn loaded_plugin(config_name: &str, skill_roots: Vec<AbsolutePathBuf>) -> LoadedPlugin<()> {
         LoadedPlugin {
             config_name: config_name.to_string(),
+            remote_plugin_id: None,
             manifest_name: None,
             plugin_namespace: Some(
                 config_name
@@ -248,8 +254,10 @@ mod tests {
     #[test]
     fn effective_plugin_skill_roots_preserves_first_plugin_for_shared_root() {
         let shared_root = test_path("shared-skills");
+        let mut first_plugin = loaded_plugin("zeta@test", vec![shared_root.clone()]);
+        first_plugin.remote_plugin_id = Some("plugins~Plugin_zeta".to_string());
         let outcome = PluginLoadOutcome::from_plugins(vec![
-            loaded_plugin("zeta@test", vec![shared_root.clone()]),
+            first_plugin,
             loaded_plugin("alpha@test", vec![shared_root.clone()]),
         ]);
 
@@ -257,7 +265,10 @@ mod tests {
             outcome.effective_plugin_skill_roots(),
             vec![PluginSkillRoot {
                 path: shared_root,
-                plugin_id: "zeta@test".to_string(),
+                plugin_identity: PluginIdentity {
+                    plugin_id: "zeta@test".to_string(),
+                    remote_plugin_id: Some("plugins~Plugin_zeta".to_string()),
+                },
                 plugin_namespace: "zeta".to_string(),
                 plugin_root: test_path("zeta@test"),
                 discovery_mode: SkillDiscoveryMode::Recursive,

codex-rs/plugin/src/plugin_id.rs

@@ -6,7 +6,7 @@ pub enum PluginIdError {
     Invalid(String),
 }
 
-#[derive(Debug, Clone, PartialEq, Eq)]
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
 pub struct PluginId {
     pub plugin_name: String,
     pub marketplace_name: String,