Add config bundle transport types (#24617)

## Summary

PR 1 of 5 in the cloud-managed config client stack.

Adds the generated backend models and client transport surface for the
config bundle endpoint. This bundle endpoint is the replacement backend
surface for legacy cloud requirements; the final PR in the stack
switches runtime consumers over to it.

## Details

- This is transport-only plumbing: no runtime config behavior changes in
this PR.
- The bundle endpoint is the new shared backend surface for
cloud-delivered config and requirements data.
- Both supported path styles are wired here: `/api/codex/config/bundle`
and `/wham/config/bundle`.
- The response types come from generated backend models so later PRs
consume the backend contract directly instead of maintaining
hand-written mirror structs.

## Validation

Validated through the targeted stack checks after rebasing onto current
`main`:

- Rust crate tests for
config/hooks/cloud-config/backend-client/app-server-protocol
- Filtered `codex-core` and `codex-app-server` `cloud_config_bundle`
tests
- Python generated-file contract test
- `cargo shear --deny-warnings`
- Targeted `argument-comment-lint` for config/hooks

codex-rs/codex-backend-openapi-models/src/models/config_bundle_response.rs

@@ -0,0 +1,40 @@
+/*
+ * codex-backend
+ *
+ * codex-backend
+ *
+ * The version of the OpenAPI document: 0.0.1
+ *
+ * Generated by: https://openapi-generator.tech
+ */
+
+use crate::models;
+use serde::Deserialize;
+use serde::Serialize;
+
+#[derive(Clone, Default, Debug, PartialEq, Serialize, Deserialize)]
+pub struct ConfigBundleResponse {
+    #[serde(
+        rename = "config_toml",
+        default,
+        with = "::serde_with::rust::double_option",
+        skip_serializing_if = "Option::is_none"
+    )]
+    pub config_toml: Option<Option<Box<models::DeliveredConfigToml>>>,
+    #[serde(
+        rename = "requirements_toml",
+        default,
+        with = "::serde_with::rust::double_option",
+        skip_serializing_if = "Option::is_none"
+    )]
+    pub requirements_toml: Option<Option<Box<models::DeliveredRequirementsToml>>>,
+}
+
+impl ConfigBundleResponse {
+    pub fn new() -> ConfigBundleResponse {
+        ConfigBundleResponse {
+            config_toml: None,
+            requirements_toml: None,
+        }
+    }
+}

codex-rs/codex-backend-openapi-models/src/models/delivered_config_toml.rs

@@ -0,0 +1,32 @@
+/*
+ * codex-backend
+ *
+ * codex-backend
+ *
+ * The version of the OpenAPI document: 0.0.1
+ *
+ * Generated by: https://openapi-generator.tech
+ */
+
+use crate::models;
+use serde::Deserialize;
+use serde::Serialize;
+
+#[derive(Clone, Default, Debug, PartialEq, Serialize, Deserialize)]
+pub struct DeliveredConfigToml {
+    #[serde(
+        rename = "enterprise_managed",
+        default,
+        with = "::serde_with::rust::double_option",
+        skip_serializing_if = "Option::is_none"
+    )]
+    pub enterprise_managed: Option<Option<Vec<models::DeliveredTomlFragment>>>,
+}
+
+impl DeliveredConfigToml {
+    pub fn new() -> DeliveredConfigToml {
+        DeliveredConfigToml {
+            enterprise_managed: None,
+        }
+    }
+}

codex-rs/codex-backend-openapi-models/src/models/delivered_requirements_toml.rs

@@ -0,0 +1,32 @@
+/*
+ * codex-backend
+ *
+ * codex-backend
+ *
+ * The version of the OpenAPI document: 0.0.1
+ *
+ * Generated by: https://openapi-generator.tech
+ */
+
+use crate::models;
+use serde::Deserialize;
+use serde::Serialize;
+
+#[derive(Clone, Default, Debug, PartialEq, Serialize, Deserialize)]
+pub struct DeliveredRequirementsToml {
+    #[serde(
+        rename = "enterprise_managed",
+        default,
+        with = "::serde_with::rust::double_option",
+        skip_serializing_if = "Option::is_none"
+    )]
+    pub enterprise_managed: Option<Option<Vec<models::DeliveredTomlFragment>>>,
+}
+
+impl DeliveredRequirementsToml {
+    pub fn new() -> DeliveredRequirementsToml {
+        DeliveredRequirementsToml {
+            enterprise_managed: None,
+        }
+    }
+}

codex-rs/codex-backend-openapi-models/src/models/delivered_toml_fragment.rs

@@ -0,0 +1,28 @@
+/*
+ * codex-backend
+ *
+ * codex-backend
+ *
+ * The version of the OpenAPI document: 0.0.1
+ *
+ * Generated by: https://openapi-generator.tech
+ */
+
+use serde::Deserialize;
+use serde::Serialize;
+
+#[derive(Clone, Default, Debug, PartialEq, Serialize, Deserialize)]
+pub struct DeliveredTomlFragment {
+    #[serde(rename = "id")]
+    pub id: String,
+    #[serde(rename = "name")]
+    pub name: String,
+    #[serde(rename = "contents")]
+    pub contents: String,
+}
+
+impl DeliveredTomlFragment {
+    pub fn new(id: String, name: String, contents: String) -> DeliveredTomlFragment {
+        DeliveredTomlFragment { id, name, contents }
+    }
+}

codex-rs/codex-backend-openapi-models/src/models/mod.rs

@@ -4,9 +4,21 @@
 // The process for this will change
 
 // Config
+pub(crate) mod config_bundle_response;
+pub use self::config_bundle_response::ConfigBundleResponse;
+
 pub(crate) mod config_file_response;
 pub use self::config_file_response::ConfigFileResponse;
 
+pub(crate) mod delivered_config_toml;
+pub use self::delivered_config_toml::DeliveredConfigToml;
+
+pub(crate) mod delivered_requirements_toml;
+pub use self::delivered_requirements_toml::DeliveredRequirementsToml;
+
+pub(crate) mod delivered_toml_fragment;
+pub use self::delivered_toml_fragment::DeliveredTomlFragment;
+
 // Cloud Tasks
 pub(crate) mod code_task_details_response;
 pub use self::code_task_details_response::CodeTaskDetailsResponse;