feat: External Secrets storage for credentials (#6477)

Github issue / Community forum post (link here to close automatically):

---------

Co-authored-by: Romain Minaud <romain.minaud@gmail.com>
Co-authored-by: Valya Bullions <valya@n8n.io>
Co-authored-by: Csaba Tuncsik <csaba@n8n.io>
Co-authored-by: Giulio Andreini <g.andreini@gmail.com>
Co-authored-by: Omar Ajoue <krynble@gmail.com>

packages/editor-ui/src/plugins/codemirror/completions/dollar.completions.ts

@@ -7,8 +7,10 @@ import {
 	prefixMatch,
 	stripExcessParens,
 	hasActiveNode,
+	isCredentialsModalOpen,
 } from './utils';
 import type { Completion, CompletionContext, CompletionResult } from '@codemirror/autocomplete';
+import { useExternalSecretsStore } from '@/stores';
 
 /**
  * Completions offered at the dollar position: `$|`
@@ -47,7 +49,24 @@ export function dollarOptions() {
 	const SKIP = new Set();
 	const DOLLAR_FUNCTIONS = ['$jmespath'];
 
-	if (!hasActiveNode()) return []; // e.g. credential modal
+	if (isCredentialsModalOpen()) {
+		return useExternalSecretsStore().isEnterpriseExternalSecretsEnabled
+			? [
+					{
+						label: '$secrets',
+						type: 'keyword',
+					},
+					{
+						label: '$vars',
+						type: 'keyword',
+					},
+			  ]
+			: [];
+	}
+
+	if (!hasActiveNode()) {
+		return [];
+	}
 
 	if (receivesNoBinaryData()) SKIP.add('$binary');