Add Swagger request/response examples for all DTOs and endpoints

[nanaf6203-bit]

Area: Developer Experience
Priority: P2 — Medium

Description

The current Swagger schema shows types but lacks realistic examples. Developers consuming the API need working examples to understand request shapes. Add @ApiProperty({ example }) decorators with realistic values.

Acceptance Criteria

• Every DTO has example values (walletAddress: GABC123..., amount: 25.5, valid dates)
• Success responses decorated with @ApiOkResponse with example payload
• Error responses decorated with @ApiBadRequestResponse, @ApiUnauthorizedResponse, @ApiNotFoundResponse, @ApiTooManyRequestsResponse with example payloads
• Realistic Stellar addresses, UUIDs, ISO timestamps, decimal amounts
• Examples render correctly in Swagger UI at /api/docs
• Document example data conventions in docs/SWAGGER.md

Technical Notes

• Use OpenAPI example field for primitives
• Use examples (object) for multiple scenarios per field
• Keep examples aligned with seeded test data

[Menjay7]

Hi! I came across this issue and would love to work on it. I have experience with similar tasks and I'm confident I can investigate, implement a clean solution, and thoroughly test it before submitting a PR. If the issue is still open, I would appreciate it if you could assign it to me. Thank you!

[MarcusDavidG]

I can handle this issue and will like to work on it, Please assign thank you.

[grantfox-oss]

🦊 GrantFox — @Menjay7 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 #60)
2. Your PR will be reviewed by the StellarTips maintainers

Good luck! Track your progress on GrantFox.