fix(api): resolve per-show scan by exact show id, not substring title (fixes #219)

POST /api/libraries/{id}/scan-show resolved the target show via
GetShowIdByTitle, an EF.Functions.Like "%title%" substring match with
no OrderBy - non-deterministic under duplicate/overlapping titles and
capable of scanning the wrong show. The Blazor UI never had this bug
(it always passed the exact show id); this endpoint shipped days ago
in PR #216 with no external consumers, so the contract break is safe.

BREAKING CHANGE: ScanShowRequest now takes `showId: int` instead of
`showTitle: string`. Replaced ITelevisionRepository.GetShowIdByTitle
with GetShowTitle(libraryId, showId), which also enforces the show
belongs to the given library. LibrariesController.ScanShow now returns
a genuine 404 ProblemDetails (via ApiResults.NotFoundProblem, the
established pre-check pattern from TemplateController.DeleteGroup)
when the show id doesn't exist in that library, then queues
QueueShowScanByLibraryId with the DB-resolved title.

SPA: libraries.ts ScanShowParams.showId replaces showTitle;
MediaDetailScreen.tsx passes show.id. Extended
ApiErrorResponseMetadataTests and OpenApiErrorResponseContractTests
with the new 404 contract for ScanShow. Regenerated v1.json / v1.d.ts
via scripts/update-openapi.sh + npm run generate:api.

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

ErsatzTV/Controllers/Api/LibrariesController.cs

@@ -1,6 +1,7 @@
 using ErsatzTV.Application.Libraries;
 using ErsatzTV.Core.Api.Libraries;
 using ErsatzTV.Core.Interfaces.Repositories;
+using ErsatzTV.Extensions;
 using MediatR;
 using Microsoft.AspNetCore.Http;
 using Microsoft.AspNetCore.Mvc;
@@ -29,27 +30,23 @@ public class LibrariesController(ITelevisionRepository televisionRepository, IMe
     [HttpPost("/api/libraries/{id:int}/scan-show")]
     [Tags("Libraries")]
     [EndpointSummary("Scan show")]
+    [ProducesResponseType(StatusCodes.Status200OK)]
+    [ProducesResponseType(typeof(ProblemDetails), StatusCodes.Status404NotFound)]
+    [ProducesResponseType(StatusCodes.Status400BadRequest)]
     public async Task<IActionResult> ScanShow(int id, [FromBody] ScanShowRequest request)
     {
-        if (string.IsNullOrWhiteSpace(request.ShowTitle))
+        Option<string> maybeTitle = await televisionRepository.GetShowTitle(id, request.ShowId);
+        foreach (string title in maybeTitle)
         {
-            return new BadRequestObjectResult(new { error = "ShowTitle is required" });
-        }
-
-        string trimmedTitle = request.ShowTitle.Trim();
-        Option<int> maybeShowId = await televisionRepository.GetShowIdByTitle(id, trimmedTitle);
-        foreach (int showId in maybeShowId)
-        {
-            bool result = await mediator.Send(new QueueShowScanByLibraryId(id, showId, trimmedTitle, request.DeepScan));
+            bool result = await mediator.Send(new QueueShowScanByLibraryId(id, request.ShowId, title, request.DeepScan));
 
             return result
                 ? new OkResult()
                 : new BadRequestObjectResult(new { error = "Unable to queue show scan. Library may not exist, may not support single show scanning, or may already be scanning." });
         }
 
-        return new BadRequestObjectResult(
-            new { error = $"Unable to locate show with title {request.ShowTitle} in library {id}" });
+        return ApiResults.NotFoundProblem($"Show {request.ShowId} does not exist in library {id}.");
     }
 }
 
-public record ScanShowRequest(string ShowTitle, bool DeepScan = false);
+public record ScanShowRequest(int ShowId, bool DeepScan = false);