feat: cat hide toggle and critical fixes (#272)

- Add 'k' key to hide/show cat in mo status
- Hand-crafted mirror frames for better left-walking animation
- Fix extra blank lines bug (strings.Lines → strings.Split)
- Fix battery power overflow (ParseInt for negative values)
- Optimize README Tips section (8 → 5 items)

cmd/status/metrics_battery.go

@@ -238,8 +238,9 @@ func collectThermal() ThermalStatus {
 				valStr, _, _ = strings.Cut(valStr, ",")
 				valStr, _, _ = strings.Cut(valStr, "}")
 				valStr = strings.TrimSpace(valStr)
-				if powerMW, err := strconv.ParseFloat(valStr, 64); err == nil {
-					thermal.BatteryPower = powerMW / 1000.0
+				// Parse as int64 first to handle negative values (charging)
+				if powerMW, err := strconv.ParseInt(valStr, 10, 64); err == nil {
+					thermal.BatteryPower = float64(powerMW) / 1000.0
 				}
 			}
 		}