Fix prototype: calibrate vision for real D2R screenshots, implement orb detection, improve dashboard

- Created debug tool (cmd/debug/main.go) to analyze real D2R screenshots and calibrate HSV ranges
- Fixed HSV color ranges for health/mana orbs based on real screenshot analysis (99.5% and 82% detection rates)
- Replaced ReadBarPercentage with ReadOrbPercentage for circular orbs (not horizontal bars)
- Added SetSource() method to capture Manager for hot-swapping capture sources
- Fixed dashboard JavaScript null reference errors with proper array checks
- Improved dashboard refresh rate from 100ms to 1000ms for better performance
- Added proper error handling for empty/null API responses
- Successfully detecting game state, health (99.5%), and mana (82%) from real D2R screenshot

pkg/engine/engine.go

@@ -201,6 +201,14 @@ func (e *Engine) LootEngine() *loot.RuleEngine {
 	return e.lootEngine
 }
 
+// SetCaptureSource swaps the capture source (for development/testing).
+func (e *Engine) SetCaptureSource(newSource capture.Source) error {
+	e.mu.Lock()
+	defer e.mu.Unlock()
+	
+	return e.captureManager.SetSource(newSource)
+}
+
 // processFrame captures and analyzes a single frame.
 func (e *Engine) processFrame() error {
 	// Capture frame