Add automatic PostgreSQL database creation and migration

- Added Jellyfin.Database.Providers.Postgres project with full EF Core migration support for PostgreSQL.
- Implemented automatic database creation and privilege assignment on startup.
- Generated initial migration and model snapshot for PostgreSQL schema.
- Updated build, test, and dependency files to include PostgreSQL provider and Npgsql packages.
- Added PowerShell script for generating and testing PostgreSQL migrations.
- No changes to application logic outside database provider/migration infrastructure.

src/Jellyfin.CodeAnalysis/obj/Debug/netstandard2.0/Jellyfin.CodeAnalysis.AssemblyInfo.cs

@@ -14,7 +14,7 @@ using System.Reflection;
 [assembly: System.Reflection.AssemblyCompanyAttribute("Jellyfin.CodeAnalysis")]
 [assembly: System.Reflection.AssemblyConfigurationAttribute("Debug")]
 [assembly: System.Reflection.AssemblyFileVersionAttribute("1.0.0.0")]
-[assembly: System.Reflection.AssemblyInformationalVersionAttribute("1.0.0+f8b7c62f9e1f477916308d6395db212ca1fca410")]
+[assembly: System.Reflection.AssemblyInformationalVersionAttribute("1.0.0+0efab2cfb69d762cf13ca5b602f93d2cccceaf5b")]
 [assembly: System.Reflection.AssemblyProductAttribute("Jellyfin.CodeAnalysis")]
 [assembly: System.Reflection.AssemblyTitleAttribute("Jellyfin.CodeAnalysis")]
 [assembly: System.Reflection.AssemblyVersionAttribute("1.0.0.0")]

src/Jellyfin.CodeAnalysis/obj/Debug/netstandard2.0/Jellyfin.CodeAnalysis.AssemblyInfoInputs.cache

@@ -1 +1 @@
-79af6817c2e15e73182d4e4594eab8c486fd3066d87d7dd560325ec905918c97
+3d4d85062f927bfd4145d798a69747c46d5f35ab7d8ff4fb93a81f8cd87c4784