fix(keyboard): dispatch modifier key events for chords

press Control+l sets the Control modifier bit on l but omits Control's own key events. Canvas apps that track modifiers through keydown/keyup therefore miss the modifier.

This dispatches modifier keys before the chord key and releases them in reverse order. It addresses the modifier-event behavior reported in #2192.

Validation:

• cd cli && cargo test --quiet -- --test-threads=1 (1,471 passed, 158 ignored)
• cd cli && cargo test e2e_press_chord_dispatches_modifier_key_events -- --ignored --nocapture
• cd cli && cargo clippy -- -D warnings