feat: Command Dead Letter Inspector Minimal API endpoints (MapCommandDeadLetterInspector)

[samtrion]

User Story

As a developer or operator managing failed commands, I want minimal API endpoints for the command dead-letter store, so that I can view failures, trigger replays, and dismiss non-replayable entries without direct database access.

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Requirements

• Create CommandDeadLetterInspectorOptions: BasePath = "/pulse/commands", RouteGroupName = "Pulse Command Dead Letter Inspector".
• Create CommandDeadLetterInspectorEndpoints (static class):
  • GET {base}/stats → ICommandDeadLetterManagement.GetStatisticsAsync()
  • GET {base}/entries?count=50&skip=0 → GetPendingAsync(count, skip)
  • GET {base}/entries/{id} → single entry or 404
  • POST {base}/entries/{id}/replay → ReplayAsync(id)
  • POST {base}/entries/{id}/dismiss → DismissAsync(id)
• Add MapCommandDeadLetterInspector(this IEndpointRouteBuilder, Action? configure = null) returning IEndpointConventionBuilder.
• No built-in authorization.

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Acceptance Criteria

• All five endpoints respond correctly.
• 404 when entry not found.
• Unit tests cover all endpoints.

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Dependencies

• Requires feat: Define CommandDeadLetterSchema constants and interfaces (feat: Define CommandDeadLetterSchema constants and interfaces (ICommandDeadLetterStore, ICommandDeadLetterManagement) #266)