feat: GTC fallback when FAK finds no liquidity (next market copy trades)

When copying a trader who buys into the next periodic market before sellers
exist, FAK returns 0 fill each attempt. After exhausting FAK retries, the
bot now falls back to a GTC limit order at price*1.02 and polls getOrder()
every 3s until filled or GTC_FALLBACK_TIMEOUT (default 60s) expires.

If the GTC times out it is cancelled. GTC_FALLBACK_TIMEOUT=0 disables the
fallback entirely.

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

src/config/index.js

@@ -49,6 +49,10 @@ const config = {
   // Skip buy if market closes within this many seconds (default 5 minutes)
   minMarketTimeLeft: parseInt(process.env.MIN_MARKET_TIME_LEFT || '300', 10),
 
+  // Seconds to wait for a GTC limit order to fill when FAK finds no liquidity
+  // (happens when copying trades into "next market" before sellers arrive)
+  gtcFallbackTimeout: parseInt(process.env.GTC_FALLBACK_TIMEOUT || '60', 10),
+
   // ── Market Maker ──────────────────────────────────────────────
   mmAssets:        (process.env.MM_ASSETS || 'btc')
                      .split(',').map((s) => s.trim().toLowerCase()).filter(Boolean),