feat: make the radiator report its own internal state

v1.1.0 loaded cleanly and still did nothing, so the NetworkValue rewrite
was not the whole story. Rather than keep guessing at which link in the
chain is dead, add indicator icons bound to the internal signals.

An indicator draws while its toggle is off, so one glance at a radiator
now separates the cases that were previously indistinguishable:

  wrench absent   -> the AddBase never merged; nothing in the mod runs
  thermal missile -> no thermal-ammo signal arriving
  resource        -> no hold signal arriving from a battery

Tests check that every added indicator binds to a component that exists
and to a sprite that exists in the indicators atlas.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_011oLWY1G6S8U35bi2FxVWni

mod.rules

@@ -16,7 +16,7 @@
 
 ID = ganter.auto_radiator
 Name = "Auto Radiator"
-Version = 1.1.0
+Version = 1.2.0
 CompatibleGameVersions = ["0.30.4c", "0.30.4"]
 ModifiesGameplay = true
 Author = "Tobias Ganter"
@@ -118,4 +118,49 @@ Actions
 			Toggle = AutoPowerToggle
 		}
 	}
+
+	// --- Diagnostic indicators -------------------------------------------
+	//
+	// An indicator icon is drawn while its toggle is OFF. These three make the
+	// radiator report its own internal state, so a radiator that is not
+	// behaving can be read directly instead of guessed at:
+	//
+	//   wrench icon      always visible -> these components merged onto the part
+	//                    absent        -> the AddBase did not take effect
+	//   thermal missile  visible       -> no thermal-ammo signal is arriving
+	//   resource icon    visible       -> no hold signal is arriving from a battery
+	//
+	// A working setup on a ship with a thermal launcher and a battery below the
+	// vent ceiling shows the wrench alone.
+	{
+		Action = AddMany
+		AddTo = "<ships/terran/radiator/radiator.rules>/Part/Components/Indicators/Indicators"
+		ManyToAdd
+		[
+			{
+				Toggle = AutoRad_AlwaysOff
+				AtlasSprite
+				{
+					File = &/INDICATORS/MissingComponent
+					Size = [1, 1]
+				}
+			}
+			{
+				Toggle = AutoRad_ThermalAmmoInUse
+				AtlasSprite
+				{
+					File = &/INDICATORS/NoThermalMissiles
+					Size = [1, 1]
+				}
+			}
+			{
+				Toggle = AutoRad_IsHolding
+				AtlasSprite
+				{
+					File = &/INDICATORS/NoResource
+					Size = [1, 1]
+				}
+			}
+		]
+	}
 ]