Store refactor - generic resource pattern and normalized entity model

[bburda]

Summary

Refactor the Zustand store to use a generic resource pattern and normalized entity model instead of per-resource-type fetch functions.

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Proposed solution (optional)

• Unified useResource(entityType, entityId, collection) instead of separate fetchConfigurations(), fetchOperations(), etc.
• Normalized entity model where all entity types (areas, components, apps, functions) are treated uniformly
• Capabilities-driven tab/resource availability - entity capabilities determine which tabs are shown
• Unified caching and loading state management across all resource collections

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Additional context (optional)

Independent architectural improvement - not blocking other feature work. New feature tabs can be added in current style first, then unified by this refactor.