Rust CLI: test coverage for `synapse graphql query`

[Mac-5]

Description
Add integration tests for synapse graphql query (implemented in Issue #86) against the mock HTTP server from Issue #64.

Scope guardrail: this PR must only touch files under cli/synapse-cli/. Do not touch anything under src/ — read the handler referenced below only to learn the request/response contract.

Requirements and context

• Cover the happy path and the documented edge case from the implement issue.
• Assert on both the process exit code and the printed output (table and --json modes).
• Depends on Issue Cursor-Based Pagination for Transaction Listing (API) #86 and Issue feat: implement api endpoint to export transaction data #64.

Suggested execution

1. Fork the repo and create a branch
   git checkout -b feature/rust-cli-test-coverage-for-synapse-graphql-query
2. Implement changes
   • Spin up the shared mock server fixture and stub the relevant endpoint(s).
   • Run the subcommand as a subprocess (or via the crate's test entrypoint) and assert on exit code + output.
   • Cover both --json and default table output.
3. Test and commit
   • Run the crate's test command and confirm it's green
   • Example commit message: test(cli): add coverage for graphql subcommand

Guidelines

• Assignment required before starting
• PR description must include: Closes #87
• PR must only touch files under cli/synapse-cli/
• Complexity: High (200 points) — Every issue in this Wave is tagged High — full points regardless of individual scope.

[innovativedesign-lab]

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

I can take this on. I've gone through the details and will provide a well-tested solution aligned with the project standards.

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

[tecmalik]

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

Hi,
Please assign me this task. I’ll implement integration tests within cli/synapse-cli/ for the synapse graphql query subcommand, covering the happy path and edge cases against the mock HTTP server for both table and JSON outputs.

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

[Onomebello]

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

Hello i would like to work on this issue

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

[marvs8]

@marvs8 has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

hi pls i'll love to work on this issue

ℹ️ Repo Maintainers: To accept this application, review their application or assign @marvs8 to this issue.

[Caneryy]

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

Hello! Can I work on this issue please?

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

[drips-wave]

Congratulations, @marvs8! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on June 30, 2026.

🧑‍💻 @marvs8: 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 🌊

[grantfox-oss]

🦊 GrantFox — @marvs8 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 #691)
2. Your PR will be reviewed by the Synapse-bridgez maintainers

Good luck! Track your progress on GrantFox.

[grantfox-oss]

🎉 This issue has been marked as completed on GrantFox!

@marvs8's PR #770 was approved and merged by @Mac-5.

🏆 @marvs8: You earned 35 FoxPoints for this contribution! Your current tier: Explorer (471 total points). Track your full progress on GrantFox.

👏 Great work, @marvs8! Keep contributing to Synapse-bridgez.