feat(DRAG-DROP): Detect Drag Start Before Movement with StartDelay Consideration

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Feature Description

The current cdkDragStarted event only fires once the user moves the mouse or touch point. However, when using the StartDelay configuration, there is no event or mechanism to detect when dragging becomes possible after the delay completes but before movement begins. This leads to a gap in functionality where developers cannot hook into the moment dragging becomes active.

Suggested Solution
Introduce an additional event (e.g., cdkDragActivated) that fires once the StartDelay has elapsed and dragging becomes possible, regardless of movement. This would enable more granular control and improve the developer experience when working with delayed drag-and-drop functionality.

Related Code/Documentation
The cdkDragStarted event: Drag and Drop Documentation

Use Case

This feature would be particularly useful for scenarios where UI feedback or logic needs to occur as soon as dragging is activated (after the delay), but before the user moves the draggable item.

For example the user wants to indicate that a element is now draggable with an outline.