Add Zod Validation for OAuth Authentication Initiation Endpoints

[Harxhit]

Summary

Add Zod validation for OAuth initiation endpoints to ensure incoming query parameters are validated before processing authentication requests.

Contexts

Currently, the OAuth initiation endpoints (/auth/google and /auth/github) directly consume query parameters such as state and mobile_redirect_uri without schema validation. Adding Zod validation will improve request safety, consistency, and maintainability.

Tasks

• Create Zod schema for OAuth initiation query parameters
• Validate query parameters in GET /auth/google
• Validate query parameters in GET /auth/github
• Return proper validation errors for invalid requests
• Add/update tests for validation behavior

Acceptance Criteria

• Invalid query parameters return validation errors
• /auth/google uses Zod validation
• /auth/github uses Zod validation
• Tests added for success and failure cases
• Documentation updated if necessary

Area

backend

Difficulty

Easy

[github-actions]

Hi @Harxhit,

Thanks for opening this issue.

Please reply with one of the following areas so the issue can be routed to the appropriate team member:

- /backend
- /web
- /mobile
- /devops

Once an area is selected, the corresponding label will be added automatically.

[Harxhit]

/backend

[github-actions]

The issue has been classified as backend.

@Harxhit, please review and triage this issue when available.

The backend label has been applied and the issue has been routed accordingly.

[ShantKhatri]

I don't think this should be under good first. @Harxhit

What should I categorise into ?

[sheeeuWu]

Hi @ShantKhatri @Harxhit , i'd like to work on this issue under gssoc'26, please assign this to me.

[Harxhit]

@sheeeuWu I have assigned this issue to you.