Added a connection status element that shows current link usage and packet loss.

scripts/link_panel.gd

@@ -0,0 +1,74 @@
+@tool
+extends PanelContainer
+
+enum Connection { CONNECTED, DEGRADED, DISCONNECTED }
+
+@export var downlink_capacity_gbps := 10.0
+@export var uplink_capacity_gbps := 10.0
+@export_range(0, 1) var warning_fraction := 0.8
+@export_range(0, 1) var fault_fraction := 0.95
+@export var loss_window_seconds := 10.0
+@export var stale_after_seconds := 2.0
+@export var link_icon: Texture2D:
+	set(value):
+		link_icon = value
+		if is_node_ready():
+			%LinkIcon.texture = value
+
+var _received_ms := -1
+var _state := Connection.CONNECTED
+var _down := 0.0
+var _up := 0.0
+var _loss := 0.0
+var _stale := false
+
+func _ready() -> void:
+	%LinkIcon.texture = link_icon
+	theme_changed.connect(_update_icon)
+	_update_icon()
+	_refresh()
+
+## Rates in Gbps; loss in percent over loss_window_seconds.
+func set_telemetry(down: float, up: float, loss_percent: float, state: int = Connection.CONNECTED) -> bool:
+	if not is_finite(down) or not is_finite(up) or not is_finite(loss_percent) or down < 0 or up < 0 or loss_percent < 0 or loss_percent > 100 or state < 0 or state > 2:
+		return false
+	_down = down
+	_up = up
+	_loss = loss_percent
+	_state = state
+	_received_ms = Time.get_ticks_msec()
+	_refresh()
+	return true
+
+func clear_telemetry() -> void:
+	_received_ms = -1
+	_refresh()
+
+func _process(_delta: float) -> void:
+	var stale := _received_ms >= 0 and Time.get_ticks_msec() - _received_ms > stale_after_seconds * 1000
+	if stale != _stale:
+		_refresh()
+
+func _refresh() -> void:
+	if not is_node_ready():
+		return
+	var missing := _received_ms < 0
+	_stale = not missing and Time.get_ticks_msec() - _received_ms > stale_after_seconds * 1000
+	var measured := not missing and _state != Connection.DISCONNECTED
+	%State.text = "NO TELEMETRY" if missing else ("STALE" if _stale else ["CONNECTED", "DEGRADED", "DISCONNECTED"][_state])
+	%State.theme_type_variation = "LinkMuted" if missing else ("LinkRateWarning" if _stale or _state == Connection.DEGRADED else ("LinkRateFault" if _state == Connection.DISCONNECTED else "Label"))
+	var gauges := [%Downlink, %Uplink]
+	for index in range(2):
+		gauges[index].capacity_gbps = maxf([downlink_capacity_gbps, uplink_capacity_gbps][index], 0.001)
+		gauges[index].warning_fraction = warning_fraction
+		gauges[index].fault_fraction = maxf(warning_fraction, fault_fraction)
+		gauges[index].rate_gbps = [_down, _up][index]
+		gauges[index].available = measured
+		gauges[index].refresh()
+	%LossValue.text = "%.2f%%" % _loss if measured else "—"
+	%LossWindow.text = "%.0f s window" % loss_window_seconds + (" · held" if _stale else "")
+
+func _update_icon() -> void:
+	var tint := get_theme_color("status_icon", "SurfaceSide")
+	tint.a = 0.06
+	%LinkIcon.self_modulate = tint