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

Emby.Server.Implementations/AppBase/BaseConfigurationManager.cs

@@ -318,8 +318,44 @@ namespace Emby.Server.Implementations.AppBase
                 Logger.LogError(ex, "Error loading configuration file: {Path}", path);
             }
 
-            return Activator.CreateInstance(configurationType)
+            // Configuration file doesn't exist, check for .example file
+            var examplePath = path + ".example";
+            var exampleFileJustCreated = false;
+
+            var defaultConfiguration = Activator.CreateInstance(configurationType)
                 ?? throw new InvalidOperationException("Configuration type can't be Nullable<T>.");
+
+            try
+            {
+                Directory.CreateDirectory(Path.GetDirectoryName(path) ?? throw new InvalidOperationException("Path can't be a root directory."));
+
+                // Create .example file if it doesn't exist
+                if (!File.Exists(examplePath))
+                {
+                    XmlSerializer.SerializeToFile(defaultConfiguration, examplePath);
+                    Logger.LogInformation("Created example configuration file: {Path}", examplePath);
+                    exampleFileJustCreated = true;
+                }
+
+                // Copy example to actual file only if example was just created or if we want to initialize from example
+                if (exampleFileJustCreated)
+                {
+                    File.Copy(examplePath, path, overwrite: false);
+                    Logger.LogInformation("Created configuration file from example: {Path}", path);
+                }
+                else
+                {
+                    // Example exists but actual doesn't - create actual with defaults (user may have customized example)
+                    XmlSerializer.SerializeToFile(defaultConfiguration, path);
+                    Logger.LogInformation("Created default configuration file: {Path}", path);
+                }
+            }
+            catch (Exception ex)
+            {
+                Logger.LogWarning(ex, "Unable to create configuration file: {Path}", path);
+            }
+
+            return defaultConfiguration;
         }
 
         /// <inheritdoc />