[codex] Support multiple forced ChatGPT workspaces (#18161)

## Summary

This change lets `forced_chatgpt_workspace_id` accept multiple workspace
IDs instead of a single value.

It keeps the existing config key name, adds backward-compatible parsing
for a single string in `config.toml`, and normalizes the setting into an
allowed workspace list across login enforcement, app-server config
surfaces, and local ChatGPT auth helpers.

## Why

Workspace-restricted deployments may need to allow more than one ChatGPT
workspace without dropping the guardrail entirely.

## Server-side impact

Codex's local server and app-server protocol needed changes because they
previously assumed a single workspace ID. The local login flow now
matches the auth backend interface by sending the allowed workspace list
as a single comma-separated `allowed_workspace_id` query parameter.

## Validation

This was tested with:

- A single workspace config
- With multi-workspace configs
- With multiple workspaces in the config
- The user only being a part of a subset of them

All were successful.

Automated coverage:

- `cargo test -p codex-login`
- `cargo test -p codex-app-server-protocol`
- `cargo test -p codex-tui local_chatgpt_auth`
- `cargo test --locked -p codex-app-server
login_account_chatgpt_includes_forced_workspace_allowlist_query_param`

codex-rs/login/src/auth/manager.rs

@@ -610,8 +610,8 @@ pub struct AuthConfig {
     pub codex_home: PathBuf,
     pub auth_credentials_store_mode: AuthCredentialsStoreMode,
     pub forced_login_method: Option<ForcedLoginMethod>,
-    pub forced_chatgpt_workspace_id: Option<String>,
     pub chatgpt_base_url: Option<String>,
+    pub forced_chatgpt_workspace_id: Option<Vec<String>>,
 }
 
 pub async fn enforce_login_restrictions(config: &AuthConfig) -> std::io::Result<()> {
@@ -653,9 +653,8 @@ pub async fn enforce_login_restrictions(config: &AuthConfig) -> std::io::Result<
         }
     }
 
-    if let Some(expected_account_id) = config.forced_chatgpt_workspace_id.as_deref() {
-        // workspace is the external identifier for account id.
-        let chatgpt_account_id = match auth {
+    if let Some(expected_account_ids) = config.forced_chatgpt_workspace_id.as_deref() {
+        let chatgpt_account_id = match &auth {
             CodexAuth::ApiKey(_) => return Ok(()),
             CodexAuth::AgentIdentity(_) => auth.get_account_id(),
             CodexAuth::Chatgpt(_) | CodexAuth::ChatgptAuthTokens(_) => {
@@ -674,13 +673,21 @@ pub async fn enforce_login_restrictions(config: &AuthConfig) -> std::io::Result<
                 token_data.id_token.chatgpt_account_id
             }
         };
-        if chatgpt_account_id.as_deref() != Some(expected_account_id) {
+
+        // workspace is the external identifier for account id.
+        let chatgpt_account_id = chatgpt_account_id.as_deref();
+        if !chatgpt_account_id.is_some_and(|actual| {
+            expected_account_ids
+                .iter()
+                .any(|expected| expected == actual)
+        }) {
+            let expected_workspaces = expected_account_ids.join(", ");
             let message = match chatgpt_account_id {
                 Some(actual) => format!(
-                    "Login is restricted to workspace {expected_account_id}, but current credentials belong to {actual}. Logging out."
+                    "Login is restricted to workspace(s) {expected_workspaces}, but current credentials belong to {actual}. Logging out."
                 ),
                 None => format!(
-                    "Login is restricted to workspace {expected_account_id}, but current credentials lack a workspace identifier. Logging out."
+                    "Login is restricted to workspace(s) {expected_workspaces}, but current credentials lack a workspace identifier. Logging out."
                 ),
             };
             return logout_with_message(
@@ -1247,7 +1254,7 @@ pub struct AuthManager {
     inner: RwLock<CachedAuth>,
     enable_codex_api_key_env: bool,
     auth_credentials_store_mode: AuthCredentialsStoreMode,
-    forced_chatgpt_workspace_id: RwLock<Option<String>>,
+    forced_chatgpt_workspace_id: RwLock<Option<Vec<String>>>,
     chatgpt_base_url: Option<String>,
     refresh_lock: Semaphore,
     external_auth: RwLock<Option<Arc<dyn ExternalAuth>>>,
@@ -1266,8 +1273,8 @@ pub trait AuthManagerConfig {
     /// Returns the CLI auth credential storage mode for auth loading.
     fn cli_auth_credentials_store_mode(&self) -> AuthCredentialsStoreMode;
 
-    /// Returns the workspace ID that ChatGPT auth should be restricted to, if any.
-    fn forced_chatgpt_workspace_id(&self) -> Option<String>;
+    /// Returns the workspace IDs that ChatGPT auth should be restricted to, if any.
+    fn forced_chatgpt_workspace_id(&self) -> Option<Vec<String>>;
 
     /// Returns the ChatGPT backend base URL used for first-party backend authorization.
     fn chatgpt_base_url(&self) -> String;
@@ -1548,7 +1555,7 @@ impl AuthManager {
         }
     }
 
-    pub fn set_forced_chatgpt_workspace_id(&self, workspace_id: Option<String>) {
+    pub fn set_forced_chatgpt_workspace_id(&self, workspace_id: Option<Vec<String>>) {
         if let Ok(mut guard) = self.forced_chatgpt_workspace_id.write()
             && *guard != workspace_id
         {
@@ -1556,7 +1563,7 @@ impl AuthManager {
         }
     }
 
-    pub fn forced_chatgpt_workspace_id(&self) -> Option<String> {
+    pub fn forced_chatgpt_workspace_id(&self) -> Option<Vec<String>> {
         self.forced_chatgpt_workspace_id
             .read()
             .ok()
@@ -1836,13 +1843,13 @@ impl AuthManager {
                 "external auth refresh did not return ChatGPT metadata",
             )));
         };
-        if let Some(expected_workspace_id) = forced_chatgpt_workspace_id.as_deref()
-            && chatgpt_metadata.account_id != expected_workspace_id
+        if let Some(expected_workspace_ids) = forced_chatgpt_workspace_id.as_deref()
+            && !expected_workspace_ids.contains(&chatgpt_metadata.account_id)
         {
             return Err(RefreshTokenError::Transient(std::io::Error::other(
                 format!(
-                    "external auth refresh returned workspace {:?}, expected {expected_workspace_id:?}",
-                    chatgpt_metadata.account_id,
+                    "external auth refresh returned workspace {:?}, expected one of {:?}",
+                    chatgpt_metadata.account_id, expected_workspace_ids,
                 ),
             )));
         }