feat: support product-scoped plugins. (#15041)

1. Added SessionSource::Custom(String) and --session-source.
  2. Enforced plugin and skill products by session_source.
  3. Applied the same filtering to curated background refresh.

codex-rs/app-server/tests/common/mcp_process.rs

@@ -96,7 +96,11 @@ pub const DEFAULT_CLIENT_NAME: &str = "codex-app-server-tests";
 
 impl McpProcess {
     pub async fn new(codex_home: &Path) -> anyhow::Result<Self> {
-        Self::new_with_env(codex_home, &[]).await
+        Self::new_with_env_and_args(codex_home, &[], &[]).await
+    }
+
+    pub async fn new_with_args(codex_home: &Path, args: &[&str]) -> anyhow::Result<Self> {
+        Self::new_with_env_and_args(codex_home, &[], args).await
     }
 
     /// Creates a new MCP process, allowing tests to override or remove
@@ -107,6 +111,14 @@ impl McpProcess {
     pub async fn new_with_env(
         codex_home: &Path,
         env_overrides: &[(&str, Option<&str>)],
+    ) -> anyhow::Result<Self> {
+        Self::new_with_env_and_args(codex_home, env_overrides, &[]).await
+    }
+
+    async fn new_with_env_and_args(
+        codex_home: &Path,
+        env_overrides: &[(&str, Option<&str>)],
+        args: &[&str],
     ) -> anyhow::Result<Self> {
         let program = codex_utils_cargo_bin::cargo_bin("codex-app-server")
             .context("should find binary for codex-app-server")?;
@@ -119,6 +131,7 @@ impl McpProcess {
         cmd.env("CODEX_HOME", codex_home);
         cmd.env("RUST_LOG", "info");
         cmd.env_remove(CODEX_INTERNAL_ORIGINATOR_OVERRIDE_ENV_VAR);
+        cmd.args(args);
 
         for (k, v) in env_overrides {
             match v {

codex-rs/app-server/tests/suite/v2/plugin_install.rs

@@ -146,6 +146,56 @@ async fn plugin_install_returns_invalid_request_for_not_available_plugin() -> Re
     Ok(())
 }
 
+#[tokio::test]
+async fn plugin_install_returns_invalid_request_for_disallowed_product_plugin() -> Result<()> {
+    let codex_home = TempDir::new()?;
+    let repo_root = TempDir::new()?;
+    std::fs::create_dir_all(repo_root.path().join(".agents/plugins"))?;
+    std::fs::write(
+        repo_root.path().join(".agents/plugins/marketplace.json"),
+        r#"{
+  "name": "debug",
+  "plugins": [
+    {
+      "name": "sample-plugin",
+      "source": {
+        "source": "local",
+        "path": "./sample-plugin"
+      },
+      "policy": {
+        "products": ["CHATGPT"]
+      }
+    }
+  ]
+}"#,
+    )?;
+    write_plugin_source(repo_root.path(), "sample-plugin", &[])?;
+    let marketplace_path =
+        AbsolutePathBuf::try_from(repo_root.path().join(".agents/plugins/marketplace.json"))?;
+
+    let mut mcp =
+        McpProcess::new_with_args(codex_home.path(), &["--session-source", "atlas"]).await?;
+    timeout(DEFAULT_TIMEOUT, mcp.initialize()).await??;
+
+    let request_id = mcp
+        .send_plugin_install_request(PluginInstallParams {
+            marketplace_path,
+            plugin_name: "sample-plugin".to_string(),
+            force_remote_sync: false,
+        })
+        .await?;
+
+    let err = timeout(
+        DEFAULT_TIMEOUT,
+        mcp.read_stream_until_error_message(RequestId::Integer(request_id)),
+    )
+    .await??;
+
+    assert_eq!(err.error.code, -32600);
+    assert!(err.error.message.contains("not available for install"));
+    Ok(())
+}
+
 #[tokio::test]
 async fn plugin_install_force_remote_sync_enables_remote_plugin_before_local_install() -> Result<()>
 {

codex-rs/app-server/tests/suite/v2/plugin_read.rs

@@ -25,6 +25,7 @@ async fn plugin_read_returns_plugin_details_with_bundle_contents() -> Result<()>
     std::fs::create_dir_all(repo_root.path().join(".agents/plugins"))?;
     std::fs::create_dir_all(plugin_root.join(".codex-plugin"))?;
     std::fs::create_dir_all(plugin_root.join("skills/thread-summarizer"))?;
+    std::fs::create_dir_all(plugin_root.join("skills/chatgpt-only"))?;
     std::fs::write(
         repo_root.path().join(".agents/plugins/marketplace.json"),
         r#"{
@@ -79,6 +80,32 @@ description: Summarize email threads
 ---
 
 # Thread Summarizer
+"#,
+    )?;
+    std::fs::write(
+        plugin_root.join("skills/chatgpt-only/SKILL.md"),
+        r#"---
+name: chatgpt-only
+description: Visible only for ChatGPT
+---
+
+# ChatGPT Only
+"#,
+    )?;
+    std::fs::create_dir_all(plugin_root.join("skills/thread-summarizer/agents"))?;
+    std::fs::write(
+        plugin_root.join("skills/thread-summarizer/agents/openai.yaml"),
+        r#"policy:
+  products:
+    - CODEX
+"#,
+    )?;
+    std::fs::create_dir_all(plugin_root.join("skills/chatgpt-only/agents"))?;
+    std::fs::write(
+        plugin_root.join("skills/chatgpt-only/agents/openai.yaml"),
+        r#"policy:
+  products:
+    - CHATGPT
 "#,
     )?;
     std::fs::write(