feat: introduce CardPhysics class to encapsulate card drag and physics state from LayoutCard.

frontend/src/desktop/LayoutSystem.ts

@@ -1,5 +1,7 @@
 import { constrainDimensions, getInitialPosition, CONTAINER_PADDING } from './utils/layoutUtils';
+
 import { fetchLayoutRecords, upsertLayoutRecords } from './db';
+import { CardPhysics } from './CardPhysics';
 
 export interface LayoutCardState {
     id: string;
@@ -26,18 +28,16 @@ export class LayoutCard implements LayoutCardState {
     private _centerX: number = 0;
     private _centerY: number = 0;
     public store: LayoutStore;
-    public dragStartX: number = 0;
-    public dragStartY: number = 0;
-    public isDirty: boolean = false;
+    public physics: CardPhysics;
     public intendedX: number = 0;
     public intendedY: number = 0;
-    private dragOffset: { x: number, y: number } | null = null;
-    public dragPointerId: number | null = null;
+    public isDirty: boolean = false;
 
     constructor(id: string, store: LayoutStore, initialData: Partial<LayoutCardState> = {}, ref: HTMLElement | null = null) {
         this.id = id;
         this.store = store;
         Object.assign(this, initialData);
+        this.physics = new CardPhysics(this);
         this.intendedX = this.x;
         this.intendedY = this.y;
         this.ref = ref;
@@ -50,12 +50,7 @@ export class LayoutCard implements LayoutCardState {
         this.applyTransform();
     }
 
-    beginDrag(offset: { x: number, y: number }, pointerId: number) {
-        this.dragOffset = offset;
-        this.dragStartX = this.x;
-        this.dragStartY = this.y;
-        this.dragPointerId = pointerId;
-    }
+
 
     getConstrainedPosition(x: number, y: number): { x: number, y: number } {
         const rad = (this.rotation * Math.PI) / 180;
@@ -77,24 +72,7 @@ export class LayoutCard implements LayoutCardState {
         return { x: newX, y: newY };
     }
 
-    continueDrag(delta: { x: number, y: number }) {
-        if (!this.dragOffset) return;
 
-        const targetX = this.x + delta.x;
-        const targetY = this.y + delta.y;
-
-        const { x: newX, y: newY } = this.getConstrainedPosition(targetX, targetY);
-
-        this.update({
-            x: newX,
-            y: newY
-        }, { markDirty: true });
-    }
-
-    finishDrag() {
-        this.dragOffset = null;
-        this.dragPointerId = null;
-    }
 
     update(changes: Partial<LayoutCardState>, options: { markDirty?: boolean, isConstraintUpdate?: boolean } = {}) {
         Object.assign(this, changes);
@@ -283,7 +261,7 @@ export class LayoutCard implements LayoutCardState {
     }
 
     get isDragging(): boolean {
-        return !!this.dragOffset;
+        return this.physics.isDragging;
     }
 }