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-vcs.el

@@ -48,9 +48,9 @@
   (setq diff-hl-flydiff-delay 0.3)
 
   ;; Make sure diff-hl updates on various events
+  ;; Note: find-file-hook not needed as global-diff-hl-mode handles it
   (add-hook 'after-save-hook 'diff-hl-update)
   (add-hook 'after-revert-hook 'diff-hl-update)
-  (add-hook 'find-file-hook 'diff-hl-update)
   (add-hook 'vc-checkin-hook 'diff-hl-update)
 
   ;; Enable globally with a slight delay to speed up initial startup