Refactor Services into Command Handlers & Sagas

[duhowise]

Migrate existing service-layer (e.g., VotingService, ElectionConfigurationService) responsibilities into

• Aggregate command handlers (single aggregate scope)
• Akkatecture Sagas (multi-aggregate, workflow coordination)

Tasks:

• Map business flows (e.g., voting, candidate registration) to command workflows/sagas.
• Implement and test saga orchestration for long-running or cross-aggregate flows.
• Use this C# process manager skeleton as scaffolding:

// Sagas/VotingSaga.cs
// ... see code example in docs