devops: staging deploy workflow triggers on every PR to any branch with no filter

[Austinaminu2]

Problem

`.github/workflows/staging.yml`'s `pull_request` trigger has no `branches:` filter (unlike `ci.yml`, which restricts to `[main]`), so every PR — including trivial doc-only ones targeting any branch — triggers a Vercel staging deploy.

Location

`.github/workflows/staging.yml` (`pull_request` trigger)

Impact

Unnecessary staging deploys run (and consume deploy quota/time) for PRs that don't need one, e.g. documentation-only changes or PRs against non-main branches.

Suggested fix

Add a `branches: [main]` filter matching `ci.yml`'s pattern, and consider a `paths-ignore` filter for docs-only changes.

[Anadudev]

@Anadudev has applied to work on this issue as part of the Stellar Wave Program's 7th wave.

I would love to take on this issue.

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[Samruto2]

@Samruto2 has applied to work on this issue as part of the Stellar Wave Program's 7th wave.

Hi Maintainer! I can fix the staging workflow so it stops deploying on every single pull request and only runs when it actually needs to. Please assign this to me

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[kelvin1738-sys]

@kelvin1738-sys has applied to work on this issue as part of the Stellar Wave Program's 7th wave.

Hello, I've carefully reviewed the issue description and have a solid understanding of the expected outcome. I'd be happy to work on this issue and deliver a solution that meets the project's requirements.

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[ghg001]

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Hello, I've read through the issue details, understand the expected outcome, and would be glad to work on it.

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[The-moving-man]

@The-moving-man has applied to work on this issue as part of the Stellar Wave Program's 7th wave.

hey maintainer, please consider my application to this

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Congratulations, @The-moving-man! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on July 30, 2026.

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[grantfox-oss]

🎉 This issue has been marked as completed on GrantFox as part of the Official Campaign | FWC26 campaign!

@The-moving-man's PR #319 was approved and merged by @Austinaminu2.

🏆 @The-moving-man: You earned 35 FoxPoints for this contribution! Your current tier: Explorer (83 total points). Track your full progress on GrantFox.

👏 Great work, @The-moving-man! Keep contributing to FlowwStar.

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This issue has been completed by @The-moving-man as part of the Stellar Wave Program's 7th Wave 🥳

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