- Agent: add stopCh to cleanly stop chat-history-cleanup goroutine on Agent.Stop()
(previously leaked a goroutine+ticker forever on every restart)
- Agent: add looksLikeStockQuery() guard to avoid hitting Sina search API on every
single message — only calls external API when text contains stock-related content
(saves ~200ms latency + API call on crypto-only queries)
- market/historical.go: safe type assertions in kline parsing (was bare .(float64)
which panics on unexpected API responses), reuse HTTP client for connection pooling
- market/api_client.go: safe comma-ok type assertions for all kline field parsing
(11 bare assertions → all guarded)
- trader/bybit: fix unsafe type assertion in CloseShort — pos["positionAmt"].(float64)
could panic if field is nil/wrong type (critical: handles real money)
