refactor: normalize FlowPilot/Assistant/ScriptBuilder to design system tokens

Replace hardcoded Tailwind color utilities with semantic CSS variable tokens
across 31 files in the FlowPilot, Assistant Chat, and Script Builder feature
communities — the areas graphify identified as design-system-free.

- text-blue-400 → text-accent, bg-blue-500/10 → bg-accent-dim, border-blue-500/20 → border-accent/20
- text-amber-400 → text-warning, bg-amber-400/10 → bg-warning-dim, border-l-amber-500 → border-l-warning
- text-rose-400/500 → text-danger, bg-rose-500/10 → bg-danger-dim
- text-emerald-400 → text-success, bg-emerald-500/10 → bg-success-dim, border-l-emerald-500 → border-l-success
- bg-white/[0.08] → bg-elevated (opacity hack → semantic surface token)
- bg-gradient-to-r from-blue-500 to-blue-400 → bg-accent (no gradient surfaces)
- bg-[#60a5fa] → bg-accent (hard-coded hex removed)

Also adds graphify-out/ to .gitignore.

Theme resilience: accent color has changed twice in 5 weeks. Semantic tokens
mean the next change is a 1-line edit in index.css, not 110 grep-and-replace.

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

frontend/src/components/flowpilot/SessionBriefing.tsx

@@ -38,7 +38,7 @@ export function SessionBriefing({
   const pkg = escalationPackage
 
   return (
-    <div className="card-flat border-l-2 border-l-amber-500 p-5 space-y-4">
+    <div className="card-flat border-l-2 border-l-warning p-5 space-y-4">
       <div>
         <h3 className="font-heading text-base font-semibold text-foreground">
           Escalation from {originalEngineerName || 'another engineer'}
@@ -60,7 +60,7 @@ export function SessionBriefing({
       {pkg.escalation_reason && (
         <div>
           <h4 className="font-sans text-xs text-[0.625rem] uppercase tracking-wider text-text-muted mb-1">Why escalated</h4>
-          <p className="text-sm text-amber-400">{pkg.escalation_reason}</p>
+          <p className="text-sm text-warning">{pkg.escalation_reason}</p>
         </div>
       )}
 
@@ -111,7 +111,7 @@ export function SessionBriefing({
           <ul className="space-y-1">
             {pkg.suggested_next_steps.map((s, i) => (
               <li key={i} className="text-sm text-foreground flex items-start gap-2">
-                <span className="text-emerald-400 mt-0.5">→</span>
+                <span className="text-success mt-0.5">→</span>
                 {s}
               </li>
             ))}