refactor: replace hardcoded hex values with Tailwind semantic tokens

3,200+ hardcoded color values replaced with CSS variable-backed
Tailwind classes (bg-card, text-foreground, border-border, etc.).
Enables light mode via CSS variable swap. Only syntax highlighting
colors and intentional one-offs remain hardcoded (~15 values).

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

frontend/src/components/scripts/ScriptParameterForm.tsx

@@ -43,7 +43,7 @@ export function ScriptParameterForm({ canGenerate }: Props) {
 
   if (parameters.length === 0) {
     return (
-      <div className="flex items-center gap-2 rounded-lg border border-border bg-[#14161d] px-3 py-3">
+      <div className="flex items-center gap-2 rounded-lg border border-border bg-card px-3 py-3">
         <Terminal size={14} className="text-muted-foreground shrink-0" />
         <p className="text-xs text-muted-foreground">
           This template has no parameters — click <span className="text-foreground font-medium">Generate</span> to produce the script.