Abstract shared Vite configuration into @cellix/config-vite package for UI applications

[nnoce14]

Overview

Create a new reusable framework package, @cellix/config-vite, that abstracts the shared Vite configuration used by all @apps/ui-* packages in the Cellix framework. This will improve maintainability, reduce duplication, and ensure consistent build setup across all UI application packages.

Acceptance Criteria

• A new package @cellix/config-vite is created in the repository
• The package follows the same conventions as @cellix/config-typescript and @cellix/config-vitest
• Common Vite configuration logic for @apps/ui-* packages is extracted and centralized in the new package
• The new package is published as a dev dependency and consumed by the @apps/ui-* packages
• Typical configuration concerns (plugins, aliases, environment consistency, cross-app sharing, etc.) are covered in the abstraction
• Setup documentation or usage example is included for package consumers

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This change will streamline UI application setup within Cellix, making upgrades and maintenance easier going forward.