[4/8] Define Python SDK public API surface (#21896)

## Why

The SDK package root should be the ergonomic public client API, not a
dump of every generated app-server schema type. Generated models still
need a supported import path, but callers should be able to tell which
names are high-level SDK entrypoints and which names are protocol value
models.

## What

- Define a curated root `__all__` for clients, handles, input helpers,
retry helpers, config, and public errors.
- Add a `types` module as the supported home for generated app-server
response, event, enum, and helper models.
- Update docs and examples to import protocol/value models from the type
module.
- Add tests that lock root exports, type-module exports, star-import
behavior, and example import hygiene.

## Stack

1. #21891 `[1/8]` Pin Python SDK runtime dependency
2. #21893 `[2/8]` Generate Python SDK types from pinned runtime
3. #21895 `[3/8]` Run Python SDK tests in CI
4. This PR `[4/8]` Define Python SDK public API surface
5. #21905 `[5/8]` Rename Python SDK package to `openai-codex`
6. #21910 `[6/8]` Add high-level Python SDK approval mode
7. #22014 `[7/8]` Add Python SDK app-server integration harness
8. #22021 `[8/8]` Add Python SDK Ruff formatting

## Verification

- Added public API signature tests for root exports, `types` exports,
and example imports.

---------

Co-authored-by: Codex <noreply@openai.com>

sdk/python/src/codex_app_server/__init__.py

@@ -1,5 +1,4 @@
-from .async_client import AsyncAppServerClient
-from .client import AppServerClient, AppServerConfig
+from .client import AppServerConfig
 from .errors import (
     AppServerError,
     AppServerRpcError,
@@ -14,29 +13,6 @@ from .errors import (
     TransportClosedError,
     is_retryable_error,
 )
-from .generated.v2_all import (
-    AskForApproval,
-    Personality,
-    PlanType,
-    ReasoningEffort,
-    ReasoningSummary,
-    SandboxMode,
-    SandboxPolicy,
-    ThreadItem,
-    ThreadForkParams,
-    ThreadListParams,
-    ThreadResumeParams,
-    ThreadSortKey,
-    ThreadSource,
-    ThreadSourceKind,
-    ThreadStartParams,
-    ThreadTokenUsageUpdatedNotification,
-    TurnCompletedNotification,
-    TurnStartParams,
-    TurnStatus,
-    TurnSteerParams,
-)
-from .models import InitializeResponse
 from .api import (
     AsyncCodex,
     AsyncThread,
@@ -58,8 +34,6 @@ from ._version import __version__
 
 __all__ = [
     "__version__",
-    "AppServerClient",
-    "AsyncAppServerClient",
     "AppServerConfig",
     "Codex",
     "AsyncCodex",
@@ -67,7 +41,6 @@ __all__ = [
     "AsyncThread",
     "TurnHandle",
     "AsyncTurnHandle",
-    "InitializeResponse",
     "RunResult",
     "Input",
     "InputItem",
@@ -76,26 +49,6 @@ __all__ = [
     "LocalImageInput",
     "SkillInput",
     "MentionInput",
-    "ThreadItem",
-    "ThreadTokenUsageUpdatedNotification",
-    "TurnCompletedNotification",
-    "AskForApproval",
-    "Personality",
-    "PlanType",
-    "ReasoningEffort",
-    "ReasoningSummary",
-    "SandboxMode",
-    "SandboxPolicy",
-    "ThreadStartParams",
-    "ThreadResumeParams",
-    "ThreadListParams",
-    "ThreadSortKey",
-    "ThreadSource",
-    "ThreadSourceKind",
-    "ThreadForkParams",
-    "TurnStatus",
-    "TurnStartParams",
-    "TurnSteerParams",
     "retry_on_overload",
     "AppServerError",
     "TransportClosedError",

sdk/python/src/codex_app_server/types.py

@@ -0,0 +1,69 @@
+"""Public generated app-server model exports for type annotations and matching."""
+
+from __future__ import annotations
+
+from .generated.v2_all import (
+    ApprovalsReviewer,
+    AskForApproval,
+    ModelListResponse,
+    Personality,
+    PlanType,
+    ReasoningEffort,
+    ReasoningSummary,
+    SandboxMode,
+    SandboxPolicy,
+    SortDirection,
+    ThreadArchiveResponse,
+    ThreadCompactStartResponse,
+    ThreadItem,
+    ThreadListCwdFilter,
+    ThreadListResponse,
+    ThreadReadResponse,
+    ThreadSetNameResponse,
+    ThreadSortKey,
+    ThreadSource,
+    ThreadSourceKind,
+    ThreadStartSource,
+    ThreadTokenUsage,
+    ThreadTokenUsageUpdatedNotification,
+    Turn,
+    TurnCompletedNotification,
+    TurnInterruptResponse,
+    TurnStatus,
+    TurnSteerResponse,
+)
+from .models import InitializeResponse, JsonObject, Notification
+
+__all__ = [
+    "ApprovalsReviewer",
+    "AskForApproval",
+    "InitializeResponse",
+    "JsonObject",
+    "ModelListResponse",
+    "Notification",
+    "Personality",
+    "PlanType",
+    "ReasoningEffort",
+    "ReasoningSummary",
+    "SandboxMode",
+    "SandboxPolicy",
+    "SortDirection",
+    "ThreadArchiveResponse",
+    "ThreadCompactStartResponse",
+    "ThreadItem",
+    "ThreadListCwdFilter",
+    "ThreadListResponse",
+    "ThreadReadResponse",
+    "ThreadSetNameResponse",
+    "ThreadSortKey",
+    "ThreadSource",
+    "ThreadSourceKind",
+    "ThreadStartSource",
+    "ThreadTokenUsage",
+    "ThreadTokenUsageUpdatedNotification",
+    "Turn",
+    "TurnCompletedNotification",
+    "TurnInterruptResponse",
+    "TurnStatus",
+    "TurnSteerResponse",
+]