[codex] Canonicalize shared workspace plugin IDs (#22564)

## Summary
- Canonicalize private and unlisted workspace shared plugin IDs to
`workspace-shared-with-me`.
- Keep `plugin/list` private/unlisted shared-with-me buckets as UI
grouping only.
- Update share read/list/checkout and cache cleanup coverage for the
canonical namespace.

## Tests
- `cargo test -p codex-app-server --test all
plugin_list_fetches_shared_with_me_kind`
- `cargo test -p codex-app-server --test all
plugin_read_returns_share_context_for_shared_remote_plugin`
- `cargo test -p codex-app-server --test all suite::v2::plugin_share`
- `cargo test -p codex-core-plugins
list_remote_plugin_shares_fetches_created_workspace_plugins`
- `cargo test -p codex-core-plugins
stale_remote_plugin_cleanup_removes_old_shared_with_me_cache_and_keeps_canonical_cache`
- `git diff --check`

codex-rs/core-plugins/src/remote/share/checkout.rs

@@ -1,3 +1,4 @@
+use super::super::REMOTE_WORKSPACE_SHARED_WITH_ME_MARKETPLACE_NAME;
 use super::super::REMOTE_WORKSPACE_SHARED_WITH_ME_PRIVATE_MARKETPLACE_NAME;
 use super::super::REMOTE_WORKSPACE_SHARED_WITH_ME_UNLISTED_MARKETPLACE_NAME;
 use super::super::RemotePluginCatalogError;
@@ -162,7 +163,8 @@ pub async fn checkout_remote_plugin_share(
 fn is_checkout_supported_share_marketplace(marketplace_name: &str) -> bool {
     matches!(
         marketplace_name,
-        REMOTE_WORKSPACE_SHARED_WITH_ME_PRIVATE_MARKETPLACE_NAME
+        REMOTE_WORKSPACE_SHARED_WITH_ME_MARKETPLACE_NAME
+            | REMOTE_WORKSPACE_SHARED_WITH_ME_PRIVATE_MARKETPLACE_NAME
             | REMOTE_WORKSPACE_SHARED_WITH_ME_UNLISTED_MARKETPLACE_NAME
     )
 }

codex-rs/core-plugins/src/remote/share/tests.rs

@@ -586,7 +586,7 @@ async fn list_remote_plugin_shares_fetches_created_workspace_plugins() {
         vec![
             RemotePluginShareSummary {
                 summary: RemotePluginSummary {
-                    id: "demo-plugin@workspace-shared-with-me-private".to_string(),
+                    id: "demo-plugin@workspace-shared-with-me".to_string(),
                     remote_plugin_id: "plugins_123".to_string(),
                     name: "demo-plugin".to_string(),
                     share_context: Some(RemotePluginShareContext {
@@ -625,7 +625,7 @@ async fn list_remote_plugin_shares_fetches_created_workspace_plugins() {
             },
             RemotePluginShareSummary {
                 summary: RemotePluginSummary {
-                    id: "demo-plugin@workspace-shared-with-me-private".to_string(),
+                    id: "demo-plugin@workspace-shared-with-me".to_string(),
                     remote_plugin_id: "plugins_456".to_string(),
                     name: "demo-plugin".to_string(),
                     share_context: Some(RemotePluginShareContext {