fix: drag speed on pan

client/ui_drag.go

@@ -11,9 +11,8 @@ import (
 /*
 Client pan integration for Fyne Draggable:
 
-- DragEvent provides absolute coordinates in "Fyne units".
-- Client knows canvasScale (Fyne units per pixel) and converts to pixels.
-- We keep last drag position and compute dx/dy ourselves.
+- DragEvent.Dragged provides per-event delta in Fyne logical units.
+- Client knows canvasScale (pixels per Fyne unit) and converts to pixels.
 - We update camera center in world-fixed (CameraXWorldFp/YWorldFp).
 
 Sign convention (map follows pointer):
@@ -24,7 +23,7 @@ Sign convention (map follows pointer):
 // draggableClient is the minimal interface we need from your client implementation.
 // If your Client already has these methods/fields, you can fold the code directly into it.
 type draggableClient interface {
-	// CanvasScale returns the fyne-units-per-pixel scale factor.
+	// CanvasScale returns pixels per Fyne logical unit.
 	CanvasScale() float32
 
 	// UpdateParams applies a mutation and schedules refresh through your coalescer.