- Added proper conditional compilation for TTL feature in contains_key methods:
  * _self_map_contains_key
  * _self_list_contains_key
  * _self_contains_key
- Without TTL feature, now directly checks underlying storage:
  * Calls _map_contains_key for map storage
  * Calls _list_contains_key for list storage
  * Calls _kv_contains_key for key-value storage
- Maintains TTL expiration checks when feature is enabled

fix(storage): improve TTL feature handling in contains_key operations

- Changed 'categories' from "Database interfaces" to "database"
  * Matches standard Rust crate categories naming
  * More consistent with other crates in ecosystem
- Maintains all other package metadata

- Bumped version from 0.6.1 to 0.7.0 (breaking changes)
- Upgraded redis dependency from 0.27 to 0.32 with new features
- Improved async iterator implementations:
  * Removed unnecessary lifetime parameters
  * Added proper error handling for all iterator operations
  * Simplified control flow with match expressions
  * Made implementations more consistent across storage backends
- Fixed key removal handling in Redis map operations
- Enhanced type safety and error propagation
- Improved code organization and readability

- Split storage backends into feature-gated modules
- Added new 'redis-cluster' feature flag
- Made sled and redis dependencies optional
- Improved conditional compilation for all storage backends
- Added proper error handling for invalid storage types
- Cleaned up imports and module organization
- Added compile-time validation for feature combinations
- Updated test configurations to work with feature flags
- Improved documentation and type safety

Dev/0.7.0

- Bumped version from 0.7.0 to 0.7.1
- Added explicit feature flags for sled and redis dependencies
- Maintained existing redis-cluster feature with its dependencies

chore: update version and refine feature flags

- Incremented package version from 0.7.1 to 0.7.2
- Added package.metadata.docs.rs configuration
- Enabled all features for documentation generation on docs.rs

- Replaced explicit feature list with `all-features = true` flag
- Maintains same documentation coverage but with simpler configuration

Dev/0.7.2

- Bumped version from 0.7.2 to 0.7.3
- Removed redundant feature check in redis-cluster module

chore: version bump and cleanup