When grab is enabled, the physical key is intercepted by evdev grab.
The engine's pop() updates the buffer but the KEY_BACKSPACE was never
injected — send_char('\x08') can't emit a keycode and fell through to
paste_string. Now backspace injects KEY_BACKSPACE press+release via
uinput directly.
- Fix tone placement for uâ, uê, uơ → tone on second vowel (e.g. tuấn, thuế, phương)
- Limit flexible backward scan to 3 chars to prevent cross-syllable modification
- Set grab = true as default config
- Add 9 new engine tests for tone placement and backtrack limit
- Simplify inject_replacement_atomic: backspaces via uinput always
- paste_string skips ydotool for non-ASCII text (crashes with 'no matching keycode')
- Use xdotool (X11) or clipboard (xclip) for Vietnamese characters
- Add detailed logging at EVERY fallback step
- Remove dead ydotoold auto-start code (not available in Ubuntu package)
- Start ydotoold automatically so ydotool can handle Vietnamese chars
- Fix xclip clipboard to run as SUDO_USER when daemon is root
- Add detailed input logging for easier debugging
- AppRun no longer sets WAYLAND_DISPLAY on X11 (checks for wayland socket)
- execute_commands now uses ydotool for both backspaces+text (same device)
- Merged execute_commands and execute_commands_with_grab into one function
- grab defaults to true in AppImage config
