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/async.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()
 
@@ -19,13 +19,15 @@ async def main() -> None:
         original = await codex.thread_start(model="gpt-5.4", config={"model_reasoning_effort": "high"})
 
         first_turn = await original.turn(TextInput("Tell me one fact about Saturn."))
-        first = await first_turn.run()
-        print("Created thread:", first.thread_id)
+        _ = await first_turn.run()
+        print("Created thread:", original.id)
 
-        resumed = await codex.thread_resume(first.thread_id)
+        resumed = await codex.thread_resume(original.id)
         second_turn = await resumed.turn(TextInput("Continue with one more fact."))
         second = await second_turn.run()
-        print(second.text)
+        persisted = await resumed.read(include_turns=True)
+        persisted_turn = find_turn_by_id(persisted.thread.turns, second.id)
+        print(assistant_text_from_turn(persisted_turn))
 
 
 if __name__ == "__main__":