Workflow Studio – Copy activities between workflows

## Feature Request

### Problem Overview
Currently, Workflow Studio supports copy-paste of activities within the same workflow.
However, it is not possible to copy an activity (or group of activities) from one workflow and paste it into another workflow.

This creates challenges when:

Reusing activities across multiple workflows.
Duplicating logic between different workflows.
Maintaining consistency without having to recreate the same activity multiple times.

### Proposed Solution
Enable cross-workflow copy-paste support for activities.
Implementation options:
When copying an activity in Workflow A, allow pasting it into Workflow B.
Support copying single activities as well as multiple selected activities.

### Alternative Solutions
Recreate the same activity manually in each workflow (time-consuming, error-prone).
Export/import the workflow JSON and manually merge activities (complex and not user-friendly).

### Use Cases
Developer designs a common pattern in Workflow A and wants to reuse it in Workflow B.
A team wants to duplicate a configured an activity across different workflows without reconfiguration.
Copying multiple related activities between workflows.

### Impact of Feature
Saves time by eliminating repetitive manual reconfiguration.
Improves consistency across workflows.
Enhances developer productivity by making reuse easier.