feat: replace orange-* Tailwind classes with blue-* equivalents

orange-400→blue-400, orange-500→blue-500, orange-600→blue-600
across ~21 component files.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

frontend/src/components/procedural/PrepareSessionModal.tsx

@@ -94,7 +94,7 @@ export function PrepareSessionModal({
         {/* Header */}
         <div className="flex items-center justify-between border-b border-border px-5 py-4">
           <div className="flex items-center gap-2">
-            <FileText className="h-4 w-4 text-orange-400" />
+            <FileText className="h-4 w-4 text-blue-400" />
             <h3 className="text-sm font-semibold text-foreground">Prepare Session</h3>
           </div>
           <button