wip: partial implementation salvaged from interrupted workflow run

Untrusted draft — no build/test had run yet. Review before building on it.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

ErsatzTV/Controllers/Api/ScheduleController.cs

@@ -99,8 +99,12 @@ public class ScheduleController(IMediator mediator) : ControllerBase
     [HttpGet("/api/schedules/{id:int}/items")]
     [Tags("Schedules")]
     [EndpointSummary("Get schedule items")]
+    [EndpointDescription(
+        "Returns the schedule's items plus a computed, best-effort runtime estimate: each item carries a " +
+        "nullable durationEstimate and the envelope carries a nullable totalDurationEstimate. Estimates are " +
+        "derived from referenced collection/media runtimes and are null when unbounded or unknown.")]
     [EndpointGroupName("general")]
-    [ProducesResponseType(typeof(List<ProgramScheduleItemViewModel>), StatusCodes.Status200OK)]
+    [ProducesResponseType(typeof(ProgramScheduleItemsWithDurationViewModel), StatusCodes.Status200OK)]
     [ProducesResponseType(typeof(ProblemDetails), StatusCodes.Status404NotFound)]
     public async Task<IActionResult> GetItems(int id, CancellationToken cancellationToken)
     {
@@ -110,8 +114,8 @@ public class ScheduleController(IMediator mediator) : ControllerBase
             return ApiResults.NotFoundProblem();
         }
 
-        List<ProgramScheduleItemViewModel> items =
-            await mediator.Send(new GetProgramScheduleItems(id), cancellationToken);
+        ProgramScheduleItemsWithDurationViewModel items =
+            await mediator.Send(new GetProgramScheduleItemsWithDurations(id), cancellationToken);
         return new OkObjectResult(items);
     }