[ghzhost]

Summary

Addresses and fixes #30 by correcting two core behavioral defects in useKeyboardShortcut:

1. Input target guard: Added isInputElement guard to prevent shortcuts from unintentionally hijacking keystrokes while the user is typing inside <input>, <textarea>, <select>, or contenteditable elements, while allowing explicit override via allowInInputs?: boolean.
2. Exact modifier matching: Fixed modifier evaluation to verify that active modifier keys (ctrlKey, metaKey, altKey, shiftKey) strictly match expected modifiers rather than only testing if the specified modifier is present, preventing spurious matches when extra held modifiers (e.g. Ctrl+Shift+K for a Ctrl+K shortcut) are pressed. Supports single modifiers or arrays of modifiers.
3. Unit tests: Added complete test suite in src/hooks/useKeyboardShortcut.test.ts covering basic match, extra modifier exclusion, composite modifiers, form control input suppression, and allowInInputs opt-in.

Closes #30