Refactor PostgreSQL provider: multi-schema & async prep

- Refactor migrations and provider to use multiple PostgreSQL schemas, each matching a legacy SQLite database (activitylog, authentication, displaypreferences, library, users).
- All tables, foreign keys, and indexes are now schema-qualified; Down migration drops tables by schema.
- Provider ensures schemas exist before migrations; entities are mapped to correct schemas in OnModelCreating.
- Add support for max-pool-size, min-pool-size, and multiplexing connection options; update logging accordingly.
- VACUUM ANALYZE now runs per schema during scheduled optimization.
- TruncateAllTablesAsync now truncates tables with schema qualification.
- README updated with schema structure, new options, and multiplexing warnings.
- CacheDecorator now calls async repository methods using .GetAwaiter().GetResult(), with documentation.
- Lays groundwork for full async/await and multiplexing support in the database layer.

MediaBrowser.Controller/Persistence/IMediaStreamRepository.cs

@@ -9,6 +9,7 @@
 using System;
 using System.Collections.Generic;
 using System.Threading;
+using System.Threading.Tasks;
 using MediaBrowser.Model.Entities;
 
 namespace MediaBrowser.Controller.Persistence;
@@ -19,17 +20,19 @@ namespace MediaBrowser.Controller.Persistence;
 public interface IMediaStreamRepository
 {
     /// <summary>
-    /// Gets the media streams.
+    /// Gets the media streams asynchronously.
     /// </summary>
     /// <param name="filter">The query.</param>
-    /// <returns>IEnumerable{MediaStream}.</returns>
-    IReadOnlyList<MediaStream> GetMediaStreams(MediaStreamQuery filter);
+    /// <param name="cancellationToken">The cancellation token.</param>
+    /// <returns>IReadOnlyList{MediaStream}.</returns>
+    Task<IReadOnlyList<MediaStream>> GetMediaStreamsAsync(MediaStreamQuery filter, CancellationToken cancellationToken = default);
 
     /// <summary>
-    /// Saves the media streams.
+    /// Saves the media streams asynchronously.
     /// </summary>
     /// <param name="id">The identifier.</param>
     /// <param name="streams">The streams.</param>
     /// <param name="cancellationToken">The cancellation token.</param>
-    void SaveMediaStreams(Guid id, IReadOnlyList<MediaStream> streams, CancellationToken cancellationToken);
+    /// <returns>A task representing the asynchronous operation.</returns>
+    Task SaveMediaStreamsAsync(Guid id, IReadOnlyList<MediaStream> streams, CancellationToken cancellationToken = default);
 }