feat(api): optional refresh param on GET /api/graphics-elements

Review SHOULD-FIX (#145): the SPA graphics picker could go stale because
Blazor ran RefreshGraphicsElements (disk->DB sync) before listing, while the
API endpoint never refreshed — a newly added .yml would not appear. GET
/api/graphics-elements?refresh=true now sends RefreshGraphicsElements before
the list query; default false leaves existing callers untouched. The playback
troubleshooting screen passes refresh=true. Controller tests cover
refresh-iff-true ordering; regenerated OpenAPI v1.json (endpoint index and
generated TS schemas unchanged - query params are not part of either).

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

ErsatzTV/Controllers/Api/GraphicsElementController.cs

@@ -12,8 +12,20 @@ public class GraphicsElementController(IMediator mediator) : ControllerBase
     [HttpGet("/api/graphics-elements", Name = "GetGraphicsElements")]
     [Tags("Graphics Elements")]
     [EndpointSummary("Get all graphics elements")]
+    [EndpointDescription(
+        "Returns all graphics elements. Pass refresh=true to first re-sync the on-disk graphics element " +
+        "definitions into the database (matching the legacy Blazor behavior) so newly added files appear.")]
     [EndpointGroupName("general")]
     [ProducesResponseType(typeof(List<GraphicsElementResponseModel>), StatusCodes.Status200OK)]
-    public async Task<List<GraphicsElementResponseModel>> GetAll(CancellationToken cancellationToken) =>
-        await mediator.Send(new GetAllGraphicsElementsForApi(), cancellationToken);
+    public async Task<List<GraphicsElementResponseModel>> GetAll(
+        [FromQuery] bool refresh,
+        CancellationToken cancellationToken)
+    {
+        if (refresh)
+        {
+            await mediator.Send(new RefreshGraphicsElements(), cancellationToken);
+        }
+
+        return await mediator.Send(new GetAllGraphicsElementsForApi(), cancellationToken);
+    }
 }