style: replace blue accent with gray and mute card badge colors

Switch all interactive UI elements (buttons, focus rings, active tabs,
FAB, links, spinners) from blue to gray to match icon colors for a
more cohesive look. Mute card badge text colors to pastels (blue-400,
green-500, purple-500) to keep the focus on card content.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/client/components/ExternalLinkDialog.tsx

@@ -38,7 +38,7 @@ export function ExternalLinkDialog() {
 					You are about to leave GearBox
 				</h3>
 				<p className="text-sm text-gray-600 mb-1">You will be redirected to:</p>
-				<p className="text-sm text-blue-600 break-all mb-6">
+				<p className="text-sm text-gray-600 break-all mb-6">
 					{externalLinkUrl}
 				</p>
 				<div className="flex justify-end gap-3">
@@ -52,7 +52,7 @@ export function ExternalLinkDialog() {
 					<button
 						type="button"
 						onClick={handleContinue}
-						className="px-4 py-2 text-sm font-medium text-white bg-blue-600 hover:bg-blue-700 rounded-lg transition-colors"
+						className="px-4 py-2 text-sm font-medium text-white bg-gray-700 hover:bg-gray-800 rounded-lg transition-colors"
 					>
 						Continue
 					</button>