refactor(config): Update Emacs configuration across multiple modules

- Prefix gptel backend names with "gptel-" for consistency
- Add denote-org-backlinks-for-heading keybinding
- Refine recentf exclusions for org journal files
- Remove org-default-priority setting
- Add gptel and denote backlink buffer rules to ibuffer
- Enable markdown-ts-mode for Emacs 31+ with truncate lines
- Add electric-pair support for equals sign
- Update popper and window management regexes for new buffer names

lisp/init-startup.el

@@ -82,7 +82,7 @@
 ;; electirc-pair-mode
 (add-hook 'org-mode-hook 'electric-pair-local-mode)
 (with-eval-after-load 'elec-pair
-  (add-to-list 'electric-pair-pairs '(?\~ . ?\~)))
+  (setq electric-pair-pairs (append '((?\~ . ?\~) (?\= . ?\=)) electric-pair-pairs)))
 
 ;; 关闭native compile警告
 (setq native-comp-async-warnings-errors-kind 'silent)