Jellyfin 11.0.0-PostgreSQL PREVIEW: version bump & defaults

- Update version to 11.0.0-PostgreSQL-PREVIEW in assemblies, installer, and build scripts
- Default web directory is now "wwwroot" across all platforms
- Configuration manager now creates .example files if missing
- Set PostgreSQL as default database with sensible options
- Postgres provider ensures database exists before table checks
- Add docs for marker conflict fixes and startup.json path issues
- Version string in logs/UI uses informational version
- Installer output filename and wizard show PREVIEW suffix
- Documentation summarizes version bump and verification steps

src/Jellyfin.Database/Jellyfin.Database.Implementations/DbConfiguration/DatabaseConfigurationOptions.cs

@@ -17,9 +17,29 @@ public class DatabaseConfigurationOptions
     /// </summary>
     public DatabaseConfigurationOptions()
     {
-        // Default to SQLite if not specified
-        DatabaseType = "Jellyfin-SQLite";
+        // Default to PostgreSQL
+        DatabaseType = "Jellyfin-PostgreSQL";
         LockingBehavior = DatabaseLockingBehaviorTypes.NoLock;
+
+        // Set up default PostgreSQL configuration
+        CustomProviderOptions = new CustomDatabaseOptions
+        {
+            PluginName = "Jellyfin-PostgreSQL",
+            PluginAssembly = "Jellyfin.Database.Providers.Postgres",
+            ConnectionString = "Host=localhost;Port=5432;Database=jellyfin;Username=jellyfin;Password=jellyfin"
+        };
+
+        // Set up default backup options
+        BackupOptions = new DatabaseBackupOptions
+        {
+            PgDumpPath = "pg_dump",
+            PgRestorePath = "pg_restore",
+            BackupFormat = "custom",
+            IncludeBlobs = true,
+            CompressionLevel = 6,
+            TimeoutSeconds = 1800,
+            VerboseOutput = true
+        };
     }
 
     /// <summary>