feat(contracts): add manual and merit-based winner selection

[heymide]

Close: #312

Pull Request Template

Description

Summary:

1. contracts/geev-core/src/types.rs :

   • SelectionMethod enum with Random , Manual , and Merit variants
   • Giveaway struct with selection_method field

2. contracts/geev-core/src/giveaway.rs :

   • create_giveaway_with_selection function for creating giveaways with non-random selection
   • finalize_manual_winners for manually selecting winners (only accessible by creator/admin)
   • finalize_merit_winners for selecting winners by reputation (only accessible by creator/admin)
   • Helper functions: ensure_ready_for_selection , ensure_creator_or_admin , validate_manual_winners , select_merit_winners , finalize_winners

3. contracts/geev-core/src/test.rs :

   • Tests for manual winner selection
   • Tests for merit-based winner selection
   • Tests for authorization checks (only creator/admin can finalize non-random winners)
   • Tests to ensure random selection still works as expected

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Checklist

• I have tested my changes locally
• I have updated documentation as needed
• I have run npx prisma generate after schema changes
• I have run npx prisma migrate dev or npx prisma migrate deploy as appropriate

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Post-Merge Steps for Maintainers

If this PR includes changes to the Prisma schema:

1. Run the following command to apply the migration to your database:

   npx prisma migrate deploy

   or, for local development:

   npx prisma migrate dev

2. Ensure your CI pipeline runs the migration before tests (add this step if missing):

   - name: Run Prisma Migrate
     run: npx prisma migrate deploy

3. Make sure the database user in CI has permission to run migrations.

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If you have any questions, please comment on this PR.

[heymide]

Done, Close: #392

[3m1n3nc3]

Hello, your CI is failing, skipping it does not fix the underlying issue. Your fork is behind the origin/main by 33 commits. Please update your fork, allow CI to run and fix any irelated issues.

Thank you.