gauge wave P1a: publish heat/power/weapon attributes + radar zoom

The gauge-databinding-map workflow found most cockpit gauges resolve NULL
because the reconstructed subsystems publish only a fraction of the attributes
the config binds.  First publishing batch (attribute tables are read-only static
data; ids kept a dense prefix from each parent's NextAttributeID):

- HeatSink table dense-append: DegradationTemperature/FailureTemperature (the
  condenser temp-bar warn/max endpoints -- were NULL, so the two-part bars could
  not scale), NormalizedPressure/DegradationPressure/CoolantMassLeakRate, and the
  HeatSink link.  Condenser/Reservoir inherit this -> all 6 condenser temp bars
  now resolve current/warn/max (verified: BT_GAUGE_ATTR_LOG all OK).
- PoweredSubsystem::GetAttributeIndex() (new) publishes InputVoltage->voltageSource
  -- the cluster power-branch gate (the power-lamp/generator-voltage/state-lamp
  sub-branch is skipped when it resolves NULL).  Flows to Sensor/Myomers/weapons.
- MechWeapon::GetAttributeIndex() (new) publishes OutputVoltage/PercentDone->
  rechargeLevel; Emitter/PPC/ProjectileWeapon/MissileLauncher/GaussRifle DefaultData
  re-pointed at it (they carried an EMPTY default-constructed index -> resolved
  NOTHING).  Verified: the ER MED LASER / PPC / STREAK weapon clusters now render
  live recharge dials (were blank TEMP/STATUS).
- Mech::SetTargetRange un-stubbed (radarRange = range) -> the radar map scale +
  overlay range readout track the mapper's zoom (was frozen at 1000).
- GAUGREND ParseAttribute: env-gated per-binding resolution trace (BT_GAUGE_ATTR_LOG)
  -- durable diagnostic infra for the wave.

Verified DBASE+dev gauges: no startup/gauge-construction crash (dense chain intact),
combat un-regressed (TARGET DESTROYED), clusters build with InputVoltage resolving.
Remaining config-binding NULLs: HeatSink/AmbientTemperature (aggregate bank, P3) +
Searchlight/LightOn (P1b).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

engine/MUNGA/GAUGREND.cpp

@@ -2180,6 +2180,12 @@ void *
 						string_pointer << "' not found\n"
 					);
 				}
+				// gauge data-binding wave: a per-binding resolution trace to the
+				// log file (env BT_GAUGE_ATTR_LOG) -- proves which cockpit bindings
+				// resolve to a live member vs read NULL (unpublished attribute).
+				if (getenv("BT_GAUGE_ATTR_LOG"))
+					DEBUG_STREAM << "[attr] " << string_pointer
+						<< (attribute_pointer ? "  OK\n" : "  NULL\n") << std::flush;
 				Check_Fpu();
 				return attribute_pointer;
 			}
@@ -2198,6 +2204,9 @@ void *
 			source << "' not found\n"
 		);
 	}
+	if (getenv("BT_GAUGE_ATTR_LOG"))
+		DEBUG_STREAM << "[attr] " << source
+			<< (attribute_pointer ? "  OK (entity)\n" : "  NULL (entity)\n") << std::flush;
 	Check_Fpu();
 	return attribute_pointer;
 }