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

early-init.el

@@ -12,7 +12,6 @@
   (scroll-bar-mode -1))			; 禁用滚动条
 (menu-bar-mode -1)			; 禁用菜单栏
 (setq display-line-numbers-type '2)
-(global-display-line-numbers-mode t)	  ; 启用行号
 (setq display-line-numbers-grow-only t)	  ; 行号栏只增不减
 (setq display-line-numbers-width-start 4) ; 预设4位宽度