Keyboard layouts and input engines share one typing workflow

dhh merged omacom/omarchy#14433 into quattro on October 10. The committed change connects installer keyboard selection to input-engine setup and adds immediate keyboard-layout and input-method selection through the Typing menu. Super+I cycles layouts and composition engines together, while Super+Shift+I cycles backward. These are development-branch changes.

Review by greptile-apps[bot] caught shortcuts losing selections without a focused text field and failed font writes leaving saved input methods inconsistent with menu checks. dhh reported fixes that retain unfocused selections and restore the previous input group after a font-write failure. omacom/omarchy#14433:discussion_r4237897756 and omacom/omarchy#14433:discussion_r4239436913 document those corrections.

xdanger proposed using Shift to leave Chinese input, with similar behavior for Japanese and Korean engines. dhh agreed to address Caps Lock and the Shift behavior in a follow-up, keeping that suggestion separate from the merged typing work. omacom/omarchy#14433:issuecomment-6098200521 and omacom/omarchy#14433:issuecomment-6098373295 record the proposal and response.