Config: extract keybinding functions and clean up key configs

- Add init-kbd-func.el for keybinding helper functions
- Move global-display-line-numbers-mode from early-init.el to init.el
- Slim down init-kbd.el: remove hydra-multiple-cursors, migrate defs
- Reorganize dirvish config
- Remove scattered global-set-key bindings from init-org, init-ui, etc.
- Guard server-start with server-running-p check
- Set ibuffer-default-sorting-mode to filename
- Tweak gptel config

lisp/init-ui.el

@@ -33,8 +33,6 @@
                           colors))))
     (string-trim (car (split-string choice)))))
 
-(global-set-key (kbd "C-c u c") 'my-color-picker)
-
 ;; rainbow mode
 (use-package rainbow-mode)