Chore: Refactor ExecuteSweepDto to Domain Command

[dimka90]

PR Description

Summary

Refactored the internal sweep execution model to accurately reflect its role as a Domain Command rather than a transport-layer DTO. This change ensures internal orchestration contracts are clearly distinguished from API payload models, aligning with NestJS architectural patterns.

Changes

• Renamed ExecuteSweepDto interface to SweepExecutionRequest.
• Renamed file from execute-sweep.dto.ts to execute-sweep.command.ts.
• Updated all internal usages in SweepsService and ValidationProvider.
• Refined variable naming across the sweeps module, replacing generic dto with descriptive command or sweepCommand.
• Added TSDoc documentation to the interface to explicitly state its purpose and prevent future misuse at controller boundaries.

Why this matters

• Architectural Clarity: Prevents confusion for new contributors by aligning terminology with NestJS expectations.
• Risk Reduction: Reduces the risk of accidentally exposing internal models as API contracts, which could bypass validation.
• Improved Readability: Descriptive naming clarifies intent in the service and validation logic.

Verification Results

All checks required by CONTRIBUTING.md have been performed and passed:

• Linting: npm run lint passed.
• Build: npm run build passed.
• Unit Tests: npm test -- sweeps.service.spec.ts passed.

Non-Goals achieved

• Zero functional regressions.
• No changes to validation logic or business rules.
• No conversion to class-based models (kept as a lightweight interface).

Closes #51