This commit extracts the keyboard shortcut handling logic from the main application entry point (`main.js`) into a new, dedicated module (`src/keyboard.js`).
Previously, all keydown event listeners were defined directly in `main.js`, mixing UI initialization with user input handling. This refactoring improves code organization and modularity by separating concerns, making the system easier to maintain and debug.
Key changes include:
- A new `src/keyboard.js` file was created to house all keyboard-related functionality.
- The `keydown` event listener and its handler function (`handleKeyDown`) were moved from `main.js` into the new module.
- An `initKeyboardShortcuts` function is now exported from `keyboard.js` and called from `main.js` during application startup.
- All dependencies required by the shortcut logic (from `dom.js`, `state.js`, `sync.js`, etc.) are now correctly imported into `keyboard.js`.
This is a pure refactoring effort and introduces no changes to application behavior.