Planner no longer has god-view. It assumes threats enter from detection boundary (unified info network earliest detection point), not route start.
Core: DetectionCalculator (EO attenuated by Visibility, radar/IR unaffected; earliest detection via segment-circle intersection). EquipmentDeployment: drop DetectionRadius, add RadarRange/EORange/IRange/DetectionAccuracy. FireUnit detection fields activated in BuildFireUnits. IDefensePlanner.Plan adds 4th param detectionSources.
Engine: BuildDetectionSources merges standalone detectors + fire-unit self-detection into unified list, passed to planner.
Fix: Solve robustness when GenerateFireEventsAt returns empty (detection boundary too late to intercept).
Tests 193 to 208 (+15). 0 warnings.
