feat: harden intelligence runtime and llm providers

apis/sources/yfinance.mjs

@@ -35,13 +35,17 @@ async function fetchQuote(symbol) {
     const url = `${BASE}/${encodeURIComponent(symbol)}?range=5d&interval=1d&includePrePost=false`;
     const data = await safeFetch(url, {
       timeout: 8000,
+      retries: 2,
+      source: `YFinance:${symbol}`,
       headers: {
         'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36',
+        'Accept': 'application/json,text/plain,*/*',
       },
     });
+    if (data?.error) throw new Error(data.error);
 
     const result = data?.chart?.result?.[0];
-    if (!result) return null;
+    if (!result) throw new Error(data?.chart?.error?.description || 'Yahoo response missing chart result');
 
     const meta = result.meta || {};
     const quotes = result.indicators?.quote?.[0] || {};