Add admin key compromise playbooks

[collinsadi]

Admin key compromise steps are not documented for multi-contract deployment.

Write playbooks for pause, freeze, admin transfer, and contract upgrade under compromise.

Acceptance criteria:

• Playbooks per contract role.
• Drill checklist included.
• Linked from SECURITY.md.

[SharifIbrahimDev]

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

Hi maintainer, I’d like to work on this issue.

I have experience with blockchain systems, security reviews, and documenting operational procedures. For this task, I’ll create clear playbooks for each contract role covering key compromise scenarios, including pause procedures, freeze actions, admin transfer, and contract upgrades. I’ll also add a practical drill checklist to validate the recovery process and ensure the documentation is linked from SECURITY.md for easy access.

I’ll keep the documentation concise, actionable, and aligned with the repository’s existing structure, and I can deliver within the Wave timeframe.

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