Improve startup performance and reduce resource usage

- Defer elfeed auto-update timers until first use (was running at startup)
- Fix consult-project-function to handle nil project gracefully
- Remove duplicate delete-trailing-whitespace hook
- Remove redundant diff-hl find-file-hook (global-diff-hl-mode handles it)
- Reduce treemacs resource usage (lower git entries, disable filewatch)
- Make dired dotfiles-first sorting opt-in (C-c s to sort, C-c S to toggle)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

lisp/init-dired.el

@@ -28,8 +28,13 @@
   (define-key dired-mode-map (kbd "* /") 'dired-mark-directories))
 
 ;; Custom sorting: directories first (dotted first), then files (dotted first)
+;; This is opt-in to avoid performance overhead on every directory open
+(defvar dired-sort-dotfiles-first-enabled nil
+  "When non-nil, automatically sort dired buffers with dotfiles first.")
+
 (defun dired-sort-dotfiles-first ()
   "Sort dired: dirs first (dots first within), then files (dots first within)."
+  (interactive)
   (save-excursion
     (let (buffer-read-only)
       (goto-char (point-min))
@@ -84,8 +89,26 @@
             (insert line "\n")))))
     (set-buffer-modified-p nil)))
 
-;; Apply custom sorting after dired reads directory
-(add-hook 'dired-after-readin-hook 'dired-sort-dotfiles-first)
+(defun dired-maybe-sort-dotfiles-first ()
+  "Sort dired buffer if `dired-sort-dotfiles-first-enabled' is non-nil."
+  (when dired-sort-dotfiles-first-enabled
+    (dired-sort-dotfiles-first)))
+
+(defun dired-toggle-dotfiles-first-sorting ()
+  "Toggle automatic dotfiles-first sorting in dired."
+  (interactive)
+  (setq dired-sort-dotfiles-first-enabled (not dired-sort-dotfiles-first-enabled))
+  (if dired-sort-dotfiles-first-enabled
+      (progn
+        (add-hook 'dired-after-readin-hook 'dired-maybe-sort-dotfiles-first)
+        (message "Dired dotfiles-first sorting enabled"))
+    (remove-hook 'dired-after-readin-hook 'dired-maybe-sort-dotfiles-first)
+    (message "Dired dotfiles-first sorting disabled")))
+
+;; Keybinding to manually sort current buffer or toggle auto-sorting
+(with-eval-after-load 'dired
+  (define-key dired-mode-map (kbd "C-c s") 'dired-sort-dotfiles-first)
+  (define-key dired-mode-map (kbd "C-c S") 'dired-toggle-dotfiles-first-sorting))
 
 (provide 'init-dired)
 ;;; init-dired.el ends here