[codex] Rename Python SDK AppServerConfig to CodexConfig (#24800)

## Why

`AppServerConfig` is exported as part of the ergonomic Python SDK
surface and passed to `Codex(...)` and `AsyncCodex(...)`. That name
exposes the underlying app-server transport at the same layer where
users are configuring the Codex client. `CodexConfig` makes the common
callsite read naturally and names the object it configures.

## What changed

- Renamed the public configuration dataclass from `AppServerConfig` to
`CodexConfig`.
- Updated `Codex`, `AsyncCodex`, and the transport clients to accept
`CodexConfig`.
- Updated binary-resolution messages, package exports, docs, examples,
and related coverage to use the new public name.

## API impact

```python
from openai_codex import Codex, CodexConfig

with Codex(config=CodexConfig(codex_bin="/path/to/codex")) as codex:
    ...
```

Callers should now import and construct `CodexConfig`; `AppServerConfig`
is no longer part of the Python SDK surface.

## Validation

- `uv run --frozen --extra dev ruff check src/openai_codex scripts
examples tests`
- Tests are deferred to online CI for this PR.

sdk/python/tests/test_client_rpc_methods.py

@@ -2,7 +2,7 @@ from __future__ import annotations
 
 from pathlib import Path
 
-from openai_codex.client import AppServerClient, _params_dict
+from openai_codex.client import CodexClient, _params_dict
 from openai_codex.generated.notification_registry import notification_turn_id
 from openai_codex.generated.v2_all import (
     AgentMessageDeltaNotification,
@@ -63,7 +63,7 @@ def test_thread_resume_response_accepts_auto_review_reviewer() -> None:
 
 
 def test_notifications_are_typed_with_canonical_v2_methods() -> None:
-    client = AppServerClient()
+    client = CodexClient()
     event = client._coerce_notification(
         "thread/tokenUsage/updated",
         {
@@ -94,7 +94,7 @@ def test_notifications_are_typed_with_canonical_v2_methods() -> None:
 
 
 def test_unknown_notifications_fall_back_to_unknown_payloads() -> None:
-    client = AppServerClient()
+    client = CodexClient()
     event = client._coerce_notification(
         "unknown/notification",
         {
@@ -110,7 +110,7 @@ def test_unknown_notifications_fall_back_to_unknown_payloads() -> None:
 
 
 def test_invalid_notification_payload_falls_back_to_unknown() -> None:
-    client = AppServerClient()
+    client = CodexClient()
     event = client._coerce_notification("thread/tokenUsage/updated", {"threadId": "missing"})
 
     assert event.method == "thread/tokenUsage/updated"
@@ -144,7 +144,7 @@ def test_generated_notification_turn_id_handles_known_payload_shapes() -> None:
 
 def test_turn_notification_router_demuxes_registered_turns() -> None:
     """The router should deliver out-of-order turn events to the matching queues."""
-    client = AppServerClient()
+    client = CodexClient()
     client.register_turn_notifications("turn-1")
     client.register_turn_notifications("turn-2")
 
@@ -187,7 +187,7 @@ def test_turn_notification_router_demuxes_registered_turns() -> None:
 
 def test_client_reader_routes_interleaved_turn_notifications_by_turn_id() -> None:
     """Reader-loop routing should preserve order within each interleaved turn stream."""
-    client = AppServerClient()
+    client = CodexClient()
     client.register_turn_notifications("turn-1")
     client.register_turn_notifications("turn-2")
 
@@ -266,7 +266,7 @@ def test_client_reader_routes_interleaved_turn_notifications_by_turn_id() -> Non
 
 def test_turn_notification_router_buffers_events_before_registration() -> None:
     """Early turn events should be replayed once their TurnHandle registers."""
-    client = AppServerClient()
+    client = CodexClient()
     client._router.route_notification(
         client._coerce_notification(
             "item/agentMessage/delta",
@@ -291,7 +291,7 @@ def test_turn_notification_router_buffers_events_before_registration() -> None:
 
 def test_turn_notification_router_clears_unregistered_turn_when_completed() -> None:
     """A completed unregistered turn should not leave a pending queue behind."""
-    client = AppServerClient()
+    client = CodexClient()
     client._router.route_notification(
         client._coerce_notification(
             "item/agentMessage/delta",
@@ -318,7 +318,7 @@ def test_turn_notification_router_clears_unregistered_turn_when_completed() -> N
 
 def test_turn_notification_router_routes_unknown_turn_notifications() -> None:
     """Unknown notifications should still route when their raw params carry a turn id."""
-    client = AppServerClient()
+    client = CodexClient()
     client.register_turn_notifications("turn-1")
     client.register_turn_notifications("turn-2")