feat: add support for scalar key types in memoization methods (#3)

- Accept string|int|float|null keys in memo(), forget(), and has() methods
- Automatically convert numeric keys to string internally for consistency

Merge pull request #2 from tomloprod/feat/runtime-flags

feat: add runtime flags for dynamic behavior control

Merge pull request #1 from tomloprod/feat/lru-cache-system

### Changes
- Add `MemoEntry` class with doubly linked list for efficient LRU operations
- Implement namespace support via `for()` method for better cache organization
- Add configurable maximum cache size with automatic eviction
- Add hit tracking and access time recording for performance analysis

### Breaking changes:
- `memo()` method now accepts nullable key for namespace scenarios
- `keys()` method replaced with getMemoizedValues() returning MemoEntry objects

chore: remove unnecessary dependency