Add Python SDK public API and examples

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

sdk/python/examples/01_quickstart_constructor/sync.py

@@ -0,0 +1,20 @@
+import sys
+from pathlib import Path
+
+_EXAMPLES_ROOT = Path(__file__).resolve().parents[1]
+if str(_EXAMPLES_ROOT) not in sys.path:
+    sys.path.insert(0, str(_EXAMPLES_ROOT))
+
+from _bootstrap import ensure_local_sdk_src, runtime_config
+
+ensure_local_sdk_src()
+
+from codex_app_server import Codex, TextInput
+
+with Codex(config=runtime_config()) as codex:
+    print("Server:", codex.metadata.server_name, codex.metadata.server_version)
+
+    thread = codex.thread_start(model="gpt-5", config={"model_reasoning_effort": "high"})
+    result = thread.turn(TextInput("Say hello in one sentence.")).run()
+    print("Status:", result.status)
+    print("Text:", result.text)