Added: Ctrl+I hotkey to focus the main chat input box.
Improved: Escape key now defocuses and restores previous message selection.
Added: Double-tap Home/End (within 800 ms) jumps to the first/last message and scrolls it into view.
Improved: Button selection for Edit/Cancel/Copy/Regenerate is language-agnostic, using visible button order and SVG icon detection.
