Add Activity Creation Functionality to Activities Sidebar Component

[oidacra]

Parent Issue

#30017

User Story

As a user, I want to be able to add new activities directly from the Activities component in the sidebar, so I can quickly create and track my tasks without navigating away from my current view.

Acceptance Criteria

• A prominent "Add Activity" button is visible within the Activities sidebar component
• Clicking the "Add Activity" button opens a textarea for creating a new activity (see the video)
• Users can submit the form to create a new activity
• The newly created activity appears immediately in the Activities list without requiring a page refresh
• The form includes proper validation to ensure all required fields are filled before submission
• A success message is displayed after successfully adding an activity
• The UI is consistent with the overall design of the dotCMS interface

Proposed Objective

• Core Features

Proposed Priority

• Priority 2 - Important

External Links... Slack Conversations, Support Tickets, Figma Designs, etc.

https://github.com/user-attachments/assets/4bf708c0-e457-4236-b38a-23ec21082aae

Assumptions & Initiation Needs

• The existing Activities component in the sidebar is fully functional
• Backend API endpoints for creating activities are already in place
• Access to the design system or UI kit to ensure consistency with existing components

Quality Assurance Notes & Workarounds

• Test the feature across different browsers and devices to ensure compatibility
• Verify that the new functionality doesn't interfere with existing sidebar features
• Check for proper error handling when network issues occur during activity creation