python-sdk: expose canonical app-server types (2026-03-16)

Remove the SDK alias/result layers so the wrapper surface returns canonical generated app-server models directly.

- delete public type alias modules and regenerate v2_all.py against current schema
- return InitializeResponse from metadata and generated Turn from run()
- update docs, examples, notebook, and tests to use canonical generated models and repo-only text extraction helpers

Validation:
- PYTHONPATH=sdk/python/src python3 -m pytest sdk/python/tests
- GH_TOKEN="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" RUN_REAL_CODEX_TESTS=1 PYTHONPATH=sdk/python/src python3 -m pytest sdk/python/tests -rs

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

sdk/python/examples/05_existing_thread/sync.py

@@ -5,7 +5,7 @@ _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
+from _bootstrap import assistant_text_from_turn, ensure_local_sdk_src, find_turn_by_id, runtime_config
 
 ensure_local_sdk_src()
 
@@ -15,9 +15,11 @@ with Codex(config=runtime_config()) as codex:
     # Create an initial thread and turn so we have a real thread to resume.
     original = codex.thread_start(model="gpt-5.4", config={"model_reasoning_effort": "high"})
     first = original.turn(TextInput("Tell me one fact about Saturn.")).run()
-    print("Created thread:", first.thread_id)
+    print("Created thread:", original.id)
 
     # Resume the existing thread by ID.
-    resumed = codex.thread_resume(first.thread_id)
+    resumed = codex.thread_resume(original.id)
     second = resumed.turn(TextInput("Continue with one more fact.")).run()
-    print(second.text)
+    persisted = resumed.read(include_turns=True)
+    persisted_turn = find_turn_by_id(persisted.thread.turns, second.id)
+    print(assistant_text_from_turn(persisted_turn))