Click an R/G/B box to edit that channel as a 0..255 value through the
unified TextInputView; the host routes keystrokes via color_picker_rgb_*
(now_ms-threaded, digit-gated, 3-char cap) and live-applies by splicing
the channel into the current RGB and committing through set_hsv.
ColorPickerState gains rgb_focus + rgb_input; active_text_input + the
text-input gate resolve it; press dispatch focuses/blurs hex vs rgb.
Extracts the hex+rgb edit state machines into color_picker_edit.rs to
keep color_picker.rs under the 800-line cap. Bumps vendor/jian to d11d54e.
d706222f4e