feat: Campaign page loading skeleton — add skeleton for contributions list and milestones

[dotunv]

Description

CampaignDetailSkeleton.jsx and ContributionListSkeleton.jsx exist but the milestones section and the backer wall have no skeleton loaders — they flash blank white space while data loads, creating a jarring layout shift.

Tasks

• Add MilestonesSkeletonLoader — 3 placeholder milestone rows with animated shimmer
• Ensure ContributionListSkeleton is actually used in Campaign.jsx while the backer wall data loads (verify it is wired up, not just defined)
• Add skeleton for the analytics charts section while Recharts data loads
• Verify skeleton heights match the rendered content to prevent cumulative layout shift (CLS)

Acceptance Criteria

• Milestones section shows shimmer placeholder while loading
• Backer wall shows shimmer rows while contributions are fetched
• No blank white flashes on initial page load
• Layout does not shift after content loads (skeleton matches final height)

[Kayce10]

@Kayce10 has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

Hi maintainer, i would like to work on this issue

ℹ️ Repo Maintainers: To accept this application, review their application or assign @Kayce10 to this issue.

[Luluameh]

@Luluameh has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

Hello,
I’ve resolved similar problems in the past and am confident I can implement a clean, efficient fix quickly if I am given the opportunity.

ℹ️ Repo Maintainers: To accept this application, review their application or assign @Luluameh to this issue.

[grantfox-oss]

🦊 GrantFox — @Luluameh has been assigned to this issue as part of the Official Campaign campaign!

Next steps:

1. Open a Pull Request referencing this issue (e.g., Closes #294)
2. Your PR will be reviewed by the Savitura maintainers

Good luck! Track your progress on GrantFox.

[drips-wave]

Congratulations, @Luluameh! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on June 30, 2026.

🧑‍💻 @Luluameh: Please resolve the issue such that the repo's maintainers have enough time to review your contribution before the due date. You'll earn Points for completing the issue on-time, which will make you eligible for a share of the Stellar Wave Program's reward pool.

Warning

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[drips-wave]

This issue has been completed by @Luluameh as part of the Stellar Wave Program's 6th Wave 🥳

😎 @Luluameh: You earned 200 Points for completing this issue! After the current Wave ends, you'll be eligible for a percentage of the Wave's reward pool based on the percentage of total points you've earned. Learn more here. You can also Leave a review to share your experience working on this issue.

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