Add JSON config, DB-backed library options, and docs

- Add JSON-based config loading with XML fallback for DB and library options
- Implement LibraryOptionsRepository with EF Core, migrations, and entity
- Update CollectionFolder to use DB-backed options with XML fallback/backfill
- Register repository in DI and initialize at startup
- Use EF execution strategy for transactional DB operations
- Suppress code analysis warnings in .csproj and test files
- Add DATABASE_MIGRATION.md, LIBRARY_OPTIONS_DB_DESIGN.md, and WEBSOCKET_AUTHENTICATION.md
- Add database.json.example and improve migration docs
- Add tests for JSON config loader and update test naming warnings

MediaBrowser.Controller/Persistence/ILibraryOptionsRepository.cs

@@ -0,0 +1,18 @@
+// <copyright file="ILibraryOptionsRepository.cs" company="PlaceholderCompany">
+// Copyright (c) PlaceholderCompany. All rights reserved.
+// </copyright>
+
+#nullable disable
+
+#pragma warning disable CS1591
+
+using MediaBrowser.Model.Configuration;
+
+namespace MediaBrowser.Controller.Persistence;
+
+public interface ILibraryOptionsRepository
+{
+    LibraryOptions GetLibraryOptions(string libraryPath);
+
+    void SaveLibraryOptions(string libraryPath, LibraryOptions options);
+}