[Docs] Remove committed scratch/PR-artifact files from the repo root

[ogazboiz]

Telegram: https://t.me/+DOylgFv1jyJlNzM0

Why this matters

Several one-off scratch/PR-artifact files are committed at the repo root (and backend root), cluttering the project and confusing newcomers about what's canonical documentation:

• ISSUE_134_SUMMARY.md
• PR_DESCRIPTION.md
• pr_102_diff.txt
• SECURITY_IMPLEMENTATION_SUMMARY.md
• SSE_IMPLEMENTATION.md (root) — note canonical SSE docs already live in backend/docs/SSE_*.md
• backend/IMPLEMENTATION_COMPLETE.md

These read like leftover working notes / generated PR text, not maintained docs.

Acceptance criteria

• Remove the scratch artifacts (pr_102_diff.txt, PR_DESCRIPTION.md, ISSUE_134_SUMMARY.md, *IMPLEMENTATION*SUMMARY/COMPLETE.md) or fold any still-relevant content into docs/
• De-duplicate root SSE_IMPLEMENTATION.md against backend/docs/SSE_IMPLEMENTATION.md
• Repo root contains only canonical top-level docs (README, CONTRIBUTING, SECURITY, etc.)

Files to touch

• ISSUE_134_SUMMARY.md, PR_DESCRIPTION.md, pr_102_diff.txt, SECURITY_IMPLEMENTATION_SUMMARY.md, SSE_IMPLEMENTATION.md, backend/IMPLEMENTATION_COMPLETE.md

Out of scope

• The maintained docs/ and backend/docs/ content.

[Stephan-Thomas]

@Stephan-Thomas has applied to work on this issue as part of the Stellar Wave Program's 5th wave.

hi, i would like to work on this.

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

[brite-side0]

@brite-side0 has applied to work on this issue as part of the Stellar Wave Program's 5th wave.

Please allow me to work on this issue with you.

ℹ️ Repo Maintainers: To accept this application, review their application or assign @brite-side0 to this issue.

[mijinummi]

@mijinummi has applied to work on this issue as part of the Stellar Wave Program's 5th wave.

Hello maintainers I'm a full stack developer experience in building scalable systems I can handle this perfectly

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

[drips-wave]

Congratulations, @mijinummi! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on June 2, 2026.

🧑‍💻 @mijinummi: 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

When opening a PR, please link it to this issue to ensure it gets tracked accurately. Points are awarded when this issue is marked as completed by the maintainer.

🤠 Repo maintainers: Please keep an eye on the contributor's progress and review their work before the due date. You can manage this issue, including adjusting its complexity and points, here.

🌊 Happy Wave 🌊

[drips-wave]

This issue has been completed by @mijinummi as part of the Stellar Wave Program's 5th Wave 🥳

😎 @mijinummi: 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.

🧑‍💻 Repo maintainers: How'd the contributor do? Leave a review to share your experience working with them.