feat: add CachedDataItem adapter for TaskStorage
Add compatibility methods that allow TaskStorage to be used with the existing
CachedDataItem-based API. This enables incremental migration from InnerStorage
to TaskStorage without changing all call sites at once.
The adapter includes:
- add_cached_data_item: Add item, return bool indicating if newly added
- insert_cached_data_item: Insert item, return old value if present
- get_cached_data_item: Get value reference by key
- contains_cached_data_item_key: Check if key exists
- remove_cached_data_item: Remove and return value
All 37 CachedDataItem variants are mapped to their corresponding TaskStorage
fields with correct semantics for each storage type (direct, auto_set, auto_map,
counter_map, auto_multimap, flag).
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude Opus 4 <noreply@anthropic.com>
