Implement emergency pause/unpause for the entire contract

[Kingsman-99]

Overview

Add a circuit-breaker pattern so the admin can halt all state-changing operations during an incident without upgrading the contract. Read-only functions remain available while paused.

Acceptance Criteria

• pause() and unpause() functions callable only by the admin
• While paused, the following functions revert with ContractPaused: create_invoice, pay_invoice, release_funds, claim_refund, raise_dispute, resolve_dispute
• Read-only functions (get_invoice, get_leaderboard, get_stats) remain usable while paused
• is_paused() view function returns the current pause state
• Emits ContractPaused { admin, ledger } and ContractUnpaused { admin, ledger } events
• Pause state stored in instance storage (survives ledger boundary)
• Integration tests: pause → verify write blocked → unpause → verify write resumes

[Emoji-dot]

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

I would like to work on this issue

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[jasmine874]

@jasmine874 has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

hello dear maintainer i would love to work along side you on this task sir.

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[Caneryy]

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

Hi maintainer, can I work on this issue?

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[drips-wave]

Congratulations, @jasmine874! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on June 30, 2026.

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