**What This PR Fixes**- Resolves type mismatch where `get_items()` returned `list[dict]` but was annotated as `list[TResponseInputItem]`- Removes unnecessary `# type: ignore` comments that masked real type safety issues- Adds explicit non-None assertion for client initialization in `start_openai_conversations_session`**Changes Made**- Added `from typing import cast` import to support explicit type casting- Typed the `all_items` accumulator as `list[TResponseInputItem]` to match method signature- Cast `item.model_dump(exclude_unset=True)` results to `TResponseInputItem` in both iteration branches- Removed `# type: ignore` on `get_items()` return statement since type now matches annotation- Removed `# type: ignore [typeddict-item]` in `pop_item()` since items are now correctly typed- Added explicit `assert _maybe_openai_client is not None` in `start_openai_conversations_session` to document invariant**Why This Matters**- Enables proper static type checking with mypy and other type checkers- Prevents potential runtime errors when downstream code expects proper `TResponseInputItem` objects- Makes type contracts explicit and verifiable- Improves code maintainability without changing runtime behavior**Backward Compatibility**- No changes to public APIs or method signatures- No changes to pagination, ordering, or session management behavior- All existing functionality preserved**Testing**- Existing test suite validates unchanged behavior- Type checking now passes without suppressions

Added type ignore comment for item_id assignment.

…ior unchanged.- Replace multiple per-item casts in get_items by accumulating plain dicts and applying a single cast at the return so the function matches its annotated return type while keeping runtime behavior identical.​- Retain a focused type ignore for item_id in pop_item because the TypedDict union does not guarantee an id key even though the API does, avoiding broader casts or schema changes in this small patch.​- Preserve ordering, pagination, and session behavior; no public API changes, no control-flow changes, and no added dependencies, making the change safe and easy to review.