fix: add Kanban menu item to sidebar navigation

[possebon]

Add missing Kanban menu entry to the main navigation sidebar. The Kanban feature was fully implemented but inaccessible through the UI due to missing sidebar configuration.

Changes:

• Add Kanban menu item with kanban icon between Contacts and Reports
• Add SIDEBAR.KANBAN translations for English and Brazilian Portuguese
• Menu item routes to /kanban with proper activeOn configuration

Technical notes:

• Backend API routes and controllers already exist
• All database migrations are applied
• Frontend components are deployed
• Access control via check_stacklab_license in KanbanItemsController
• Policy-based permissions: agents can view/edit, admins can delete

Related: Kanban feature integration

Pull Request Template

Description

Please include a summary of the change and issue(s) fixed. Also, mention relevant motivation, context, and any dependencies that this change requires.
Fixes # (issue)

Type of change

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• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality not to work as expected)
• This change requires a documentation update

How Has This Been Tested?

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Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my code
• I have commented on my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules