Feature/admin contract simulation

[uche102]

Summary

Provides admins with a smart contract dry-run simulation sandbox to preview state storage mutations, emitted events, gas consumption, and execution status prior to submitting transactions on-chain.

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Acceptance Criteria Covered

• Dry-run Simulation Sandbox: Executes contract entry points against an isolated virtual environment without mutating on-chain or database state.
• State Diffs & Emitted Events: Reports storage key diffs (before vs after) and structured event logs.
• Zero On-Chain Mutations: Dry-runs run completely in-memory with zero persistent side-effects.
• Admin UI Results Surface: Interactive Admin UI dashboard surfaces simulation metrics and state diffs before execution.
• Public Contract Entry Points: Supports CredentialRegistry, TokenStaking, GovernanceVault, and Custom Soroban entry points.

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Files Changed

• backend/src/services/simulation/contractSimulationService.ts (New)
• backend/src/routes/admin/simulate.ts (New)
• backend/src/index.ts (Modified)
• frontend/src/app/admin/simulate/page.tsx (New)
• frontend/src/components/Admin/AdminSidebar.tsx (Modified)

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Branch Information

• Branch: feature/admin-contract-simulation
• URL: https://github.com/uche102/AetherMint/pull/new/feature/admin-contract-simulation
  -Closes [Contracts] Contract dry-run sandbox for administrators #424