Code Farm: per-plot auto-replant pause and crop-lock check; community sync and node work

Continuous Delivery could never be turned off once a crop was planted. Add a
one-shot per-plot "stop after harvest" flag (POST /game/plot/stop, Devii tool
game_plot_stop, game_plots.stop_after_harvest), cleared by the next plant,
autoreplant claim or Refactor. Autoreplant now also respects crop locks through
the shared _crop_lock predicate. Plan and measurements in happyplanting.md.

Also includes the pending community sync, node network and related work in the
tree; the full suite passed (4999) with all of it.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

nodes/client/battery_windows.go

@@ -0,0 +1,28 @@
+//go:build windows
+
+package main
+
+import (
+	"syscall"
+	"unsafe"
+)
+
+type systemPowerStatus struct {
+	ACLineStatus        byte
+	BatteryFlag         byte
+	BatteryLifePercent  byte
+	SystemStatusFlag    byte
+	BatteryLifeTime     uint32
+	BatteryFullLifeTime uint32
+}
+
+var getSystemPowerStatus = syscall.NewLazyDLL("kernel32.dll").NewProc("GetSystemPowerStatus")
+
+func systemBattery() (bool, error) {
+	var status systemPowerStatus
+	result, _, err := getSystemPowerStatus.Call(uintptr(unsafe.Pointer(&status)))
+	if result == 0 {
+		return false, err
+	}
+	return windowsOnBattery(status.ACLineStatus, status.BatteryFlag), nil
+}