Make admin transfer two-step to prevent bricking the registry

[priscaenoch]

Problem

transfer_admin in explorer/src/lib.rs sets the new admin in a single step: it authorizes the current admin, then immediately writes DataKey::Admin to the provided new_admin. Every privileged operation (pause, set_max_events, register_contract, submit_event, etc.) is gated on that address. If the admin transfers to a mistyped or uncontrolled address, the contract is permanently bricked with no way to recover control, because there is no upgrade path either.

What needs to be done

• Replace the single-step transfer with a two-step nominate/accept flow:
  • transfer_admin(new_admin) records a pending admin (does not change the active admin).
  • accept_admin() requires require_auth from the pending admin and only then promotes it to active admin.
• Add a way for the current admin to cancel a pending transfer before it is accepted.
• Emit events for nomination, acceptance, and cancellation, and extend the instance TTL on each write.
• Keep the existing typed Error variants and add any needed new ones.

Files

• explorer/src/lib.rs

Acceptance deliverables

• Admin rights only move once the nominated address actively accepts.
• A pending transfer can be cancelled by the current admin.
• All CI checks pass; the change cannot be merged until CI is green.

Tests to pass

• Test: after transfer_admin, the current admin still controls the contract until accept_admin.
• Test: only the pending admin can accept_admin.
• Test: the current admin can cancel a pending transfer.

[Ayinkx01]

Hi i would like to work on this issue please assign to me
I can do it perfectly

[Ayinkx01]

Hi i would like to work on this issue please assign to me
I can do it perfectlyHi i would like to work on this issue please assign to me
I can do it perfectly

[zhero-o]

I'd like to work on this issue. Can I get assigned?

[grantfox-oss]

🦊 GrantFox — @zhero-o has been assigned to this issue as part of the Third Campaign campaign!

Next steps:

1. Open a Pull Request referencing this issue (e.g., Closes #27)
2. Your PR will be reviewed by the octraban maintainers

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[grantfox-oss]

🎉 This issue has been marked as completed on GrantFox as part of the Third Campaign campaign!

@zhero-o's PR #32 was approved and merged by @priscaenoch.

🏆 @zhero-o: You earned 35 FoxPoints for this contribution! Your current tier: Explorer (532 total points). Track your full progress on GrantFox.

👏 Great work, @zhero-o! Keep contributing to octraban.