fix: HL balance now reads spot USDC via SpotUserState

HL testnet USDC lives in the spot account, not the perp clearinghouse.
GetBalance() was calling UserState() (perp clearinghouseState), which
returned /usr/bin/bash. Switched to SpotUserState() and parse USDC.total - USDC.hold.

Also cleaned up .gitignore to exclude .env, binary, logs, data/.

scanner.go

@@ -19,7 +19,7 @@ var takerFees = map[string]float64{
 // TickerCoins defines all coins we monitor.
 var TrackedCoins = []TrackedCoin{
 	{Name: "DOGE", BN: "DOGEUSDT", BG: "DOGEUSDT", HL: "DOGE"},
-	{Name: "LINK", BN: "LINKUSDT", BG: "LINKUSDT", HL: "LINK"},
+	// LINK removed — not listed on HL testnet
 	{Name: "ONDO", BN: "ONDOUSDT", BG: "ONDOUSDT", HL: "ONDO"},
 	{Name: "OP", BN: "OPUSDT", BG: "OPUSDT", HL: "OP"},
 	{Name: "WIF", BN: "WIFUSDT", BG: "WIFUSDT", HL: "WIF"},