perf: optimize tramp + projectile integration

Reduce how much projectile hits the server in TRAMP buffers by:

- Not looking for fd/fdfind (just use the VCS-specific commands
  projectile provides and assume they're present on the remote).
- Not walking up the directory tree to display the project name in the
  mode line.
- Reducing TRAMP file-cache misses.
- Reducing how chatty tramp is about its connections.

Fix #5360

core/core-editor.el

@@ -411,6 +411,16 @@ files, so this replace calls to `pp' with the much faster `prin1'."
     (server-start)))
 
 
+(after! tramp
+  (setq remote-file-name-inhibit-cache 60
+        tramp-completion-reread-directory-timeout 60
+        tramp-verbose 1
+        vc-ignore-dir-regexp (format "%s\\|%s\\|%s"
+                                     vc-ignore-dir-regexp
+                                     tramp-file-name-regexp
+                                     "[/\\\\]node_modules")))
+
+
 ;;
 ;;; Packages
 

core/core-projects.el

@@ -36,7 +36,15 @@ debian, and derivatives). On most it's 'fd'.")
         projectile-kill-buffers-filter 'kill-only-files
         projectile-known-projects-file (concat doom-cache-dir "projectile.projects")
         projectile-ignored-projects '("~/")
-        projectile-ignored-project-function #'doom-project-ignored-p)
+        projectile-ignored-project-function #'doom-project-ignored-p
+
+        ;; The original `projectile-default-mode-line' can be expensive over
+        ;; TRAMP, so we gimp it in remote buffers.
+        projectile-mode-line-function
+        (lambda ()
+          (if (file-remote-p default-directory)
+              (projectile-default-mode-line)
+            "")))
 
   (global-set-key [remap evil-jump-to-tag] #'projectile-find-tag)
   (global-set-key [remap find-tag]         #'projectile-find-tag)
@@ -147,13 +155,14 @@ c) are not valid projectile projects."
   ;; HACK Don't rely on VCS-specific commands to generate our file lists. That's
   ;;      7 commands to maintain, versus the more generic, reliable and
   ;;      performant `fd' or `ripgrep'.
-  (defadvice! doom--only-use-generic-command-a (vcs)
+  (defadvice! doom--only-use-generic-command-a (fn vcs)
     "Only use `projectile-generic-command' for indexing project files.
 And if it's a function, evaluate it."
-    :override #'projectile-get-ext-command
-    (if (functionp projectile-generic-command)
+    :around #'projectile-get-ext-command
+    (if (and (functionp projectile-generic-command)
+             (not (file-remote-p default-directory)))
         (funcall projectile-generic-command vcs)
-      projectile-generic-command))
+      (funcall fn vcs)))
 
   ;; `projectile-generic-command' doesn't typically support a function, but my
   ;; `doom--only-use-generic-command-a' advice allows this. I do it this way so