Testing: coverage reporting + minimum thresholds per package/crate

[Depo-dev]

Summary

Add coverage reporting across Rust, Go, and the SDKs with enforced minimum thresholds on critical packages.

Background & current behaviour

Test suites exist across Rust, Go, and the SDKs (SDK suites were wired into CI in #192), but there is no coverage visibility and no gate, so MVP-critical paths could silently lose test coverage.

Why this matters for MVP

Coverage visibility + a floor on critical packages prevents regression in test quality as the codebase grows toward MVP.

Proposed implementation

1. Collect coverage: Rust (cargo llvm-cov), Go (go test -coverprofile), TS/Python SDKs (vitest/coverage, pytest-cov).
2. Upload reports (CI artifact and/or Codecov) and display a summary on PRs.
3. Enforce a minimum threshold on MVP-critical packages (parser, streamer/db, auth, handlers) — not necessarily the whole tree.
4. Document how to run coverage locally.

Acceptance criteria

• Coverage collected for Rust, Go, and TS/Python SDKs.
• Reports uploaded (artifact or Codecov) + PR summary.
• Minimum threshold enforced on critical packages/crates.
• Local coverage instructions documented.

Affected files / components

• .github/workflows/ci.yml
• per-language coverage/test configs

Testing & verification

CI produces coverage reports; dropping coverage on a critical package below the floor fails the build.

Related / dependencies

Builds on the wired SDK test suites (#192) + contract tests (#324).

Out of scope

100%-coverage mandates across the whole repo.

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Target branch

All work for this issue MUST target the dev branch. Cut your feature branch from dev and open the pull request against dev, never against main. Any PR opened against main for this issue will be closed and asked to re-target dev.

[deltron-fr]

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

I would like to work on this issue

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[josephchimebuka]

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

Hi GM, I have reviewed this issue and taken the time to understand the requirements, current implementation, and the expected outcome. Based on my analysis, I believe this is something I can successfully handle and contribute to... Kindly assign

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

[drips-wave]

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

🧑‍💻 @josephchimebuka: 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.

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