bringIntoView returned the last boundingBox() unconditionally after the
scroll loop exhausted, so an element still outside the viewport would be
clicked anyway. Validate the final box against the actual viewport bounds
on both axes (innerWidth/innerHeight) and return null otherwise, so
humanClick fails instead of clicking an off-screen coordinate.
Address review accuracy: humanClick used DOM scrollIntoViewIfNeeded and fell
back to Playwright locator.click() when an element had no box - neither is real
input. Now it brings elements into view with a real wheel scroll and throws if
there is no on-screen box (no synthetic click). Header comment and README
corrected: xdotool injects synthetic X input (not a physical HID device), and
all actions are real input while the CDP/DOM API is used only to read state.
Make every action real keyboard/mouse via xdotool, not just the visible
browsing: address-bar navigation (Ctrl+L + char-by-char typing), the YouTube
settings gear -> 화질 -> 1080p menu (real clicks, verified hd1080), the autoplay
toggle, the play button, and fullscreen via the real 'f' key (F11 isn't honored
by this WM; 'f' yields true 1080p fullscreen without pausing). CDP/DOM API is
now used only to read state for verification.
