Fix: usage shifts

[ItzNotABug]

What does this PR do?

Fixes the usage layout shift.

Test Plan

Manual.

Before -

https://github.com/user-attachments/assets/04deef4a-1be7-4eeb-a5fc-81c3e09f99df

After -

https://github.com/user-attachments/assets/2c0bf80e-a044-4032-9471-b2c384a0f6a5

Related PRs and Issues

N/A.

Have you read the Contributing Guidelines on issues?

Yes.

Summary by CodeRabbit

• New Features

  • Charts can opt out of built-in visual styling and accept a new option to control chart update/merge behavior.
  • Cards gain an option to make inner content fill available height.
  • Seeded fake data generators for chart previews.
  • New simple and extended skeleton metric components for overview pages.

• Performance

  • Client-side caching for usage data and a minimum loading display time to avoid flicker; loading state exposed.

• UX Improvements

  • Period selectors disabled while loading; consistent skeleton-driven loading and improved no-data presentation.

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