feat: add useSwitcher hook with tests and documentation

[sam3690]

Description

Adds a new useSwitcher hook that provides explicit control functions for boolean state management.

Features

• Returns a tuple with [state, turnOn, turnOff, toggle]
• Similar to useToggle but with dedicated functions for better code clarity
• Default value support (defaults to false)
• Memoized functions using useCallback for performance

Changes

• ✅ Implemented useSwitcher hook in src/useSwitcher.ts
• ✅ Added comprehensive test suite (12 tests, all passing)
• ✅ Added documentation with examples
• ✅ Exported hook in main index.ts

Testing

All tests pass:

npm test -- useSwitcher.test.ts
# ✓ 12 tests passing

Example Usage

const [isOpen, openModal, closeModal, toggleModal] = useSwitcher();