Introduce `_request_json` method for async JSON requests and improved error handling. Add static methods `_normalize_payload`, `_split_context`, `_ensure_list`, and `_build_model_info` to parse and normalize API responses. These changes improve the robustness of the CivArchiveClient by ensuring consistent data structures and handling potential API response issues gracefully.
* add CivArchive API
* Oops, missed committing this part when I updated codebase to latest version
* Adjust API for version fetching and solve the broken API (hash gives only files, not models - likely to be fixed but in the meantime...)
* add asyncio import to allow timeout cooldown
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Co-authored-by: Scruffy Nerf <Scruffynerf@duck.com>