[SCF high][easy] Add request limits to public readiness endpoints

[karagozemin]

Goal\nProtect public coordinator and resolver diagnostics from oversized or repeated requests.\n\n## Acceptance criteria\n- Enforce a small request-size limit.\n- Return stable 413 and 429 responses.\n- Add limit and normal-request tests.\n\n## Complexity\nHigh - small implementation, high reliability value.

[p70436464-prog]

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I’m interested in contributing to this issue and would be happy to work on it

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[AbuJulaybeeb]

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Hi Maintainer, haven reviewed the description of the issue, and well experienced with Js Library,
I would like to hop on the issue and sure to deliver at ETA 2hrs

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[VeronicDev]

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Hi! I can fix this pls assign

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[TheFaith-Code]

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Hi, I'd like to work on this issue.

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[CollinsKRO]

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Hi, I can fix this kindly assign.

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[MerlinTheWhiz]

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Hi there, please can I work on this

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[Muyideen-js]

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Hi, I can fix this

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[Fayedamz]

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Hello Maintainer, I'd love to work on this issue.

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[hardeyshorlar12]

@hardeyshorlar12 has applied to work on this issue as part of the Stellar Wave Program's 8th wave.

Hello Maintainer, I’m genuinely asking for an opportunity to work on this issue. I’d really appreciate being given the chance to contribute to the issue

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[young-wallace]

@young-wallace has applied to work on this issue as part of the Stellar Wave Program's 8th wave.

Hi Maintainer, haven reviewed the description of the issue, and well experienced with Js Library,
I would like to hop on the issue and sure to deliver at ETA 2hrs

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[oscarj007]

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Pls can I work on this issue

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