feat: WTI/Brent via Stooq, PMI scraping (TE), Groq replace Bytez

- drivers: switch Brent (cb.f) and WTI (cl.f) from stale FRED to Stooq
  near-real-time futures — same stooqMetal() already used for gold/silver
- macro: add scrapePMI() to scrape Trading Economics meta description for
  manufacturing-pmi and services-pmi for all 8 currencies (no API key needed)
- narrative: replace dead Bytez API with Groq (OpenAI-compatible, free tier)
  env var renamed BYTEZ_API_KEY → GROQ_API_KEY, model llama-3.1-8b-instant
- NarrativeButton: rebrand "Erreur Bytez" / "Bytez AI" → "Erreur IA" / "Groq AI"

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

components/NarrativeButton.tsx

@@ -53,7 +53,7 @@ export default function NarrativeButton({ currency, indicators, macroScore }: Pr
 
       {error && (
         <span className="text-[10px] text-red-500 truncate max-w-[140px]" title={error}>
-          Erreur Bytez
+          Erreur IA
         </span>
       )}
 
@@ -66,7 +66,7 @@ export default function NarrativeButton({ currency, indicators, macroScore }: Pr
             <div className="flex items-center justify-between mb-3">
               <div className="flex items-center gap-2">
                 <Sparkles size={15} className="text-indigo-500" />
-                <span className="font-medium text-sm">Analyse {currency} — Bytez AI</span>
+                <span className="font-medium text-sm">Analyse {currency} — Groq AI</span>
               </div>
               <button onClick={() => setOpen(false)} className="text-gray-400 hover:text-gray-700">
                 <X size={15} />
@@ -74,7 +74,7 @@ export default function NarrativeButton({ currency, indicators, macroScore }: Pr
             </div>
             <p className="text-sm text-gray-700 leading-relaxed whitespace-pre-wrap">{analysis}</p>
             <div className="mt-3 text-[10px] text-gray-400 text-right">
-              Powered by Bytez · Llama 3.1 8B
+              Powered by Groq · Llama 3.1 8B
             </div>
           </div>
         </div>