Fix ui reset on wake project navigation

[ericokuma]

Fixes an issue where the "waking project" UI banner would disappear when navigating between project pages (e.g., to settings).

The problem stemmed from:

1. BillingCTAHandler instances not correctly sharing state across components.
2. The BillingCTAHandler.get() method incorrectly resetting the wakingProjects state.
3. The project layout (/[organization]/[project]/+layout.svelte) not being aware of the organization-level project wake process.

The fix ensures the wake state persists across navigation by:

1. Consistently using the singleton BillingCTAHandler.get().
2. Removing the problematic state reset from BillingCTAHandler.get().
3. Updating the project layout to check and display the organization-level wake status, providing a consistent UI experience during the wake process.

Checklist:

• [x] Covered by tests (manual testing performed, unit tests not applicable for this UI state fix)
• [x] Ran it and it works as intended
• [x] Reviewed the diff before requesting a review
• [x] Checked for unhandled edge cases
• [x] Linked the issues it closes (Closes ENG-46)
• [ ] Checked if the docs need to be updated. If so, create a separate Linear DOCS issue
• [ ] Intend to cherry-pick into the release branch
• [x] I'm proud of this work!

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Linear Issue: ENG-46

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