added ServerConfigurationMapping

split up Abstractions so we have one type per file.

pgLabII.PgUtils/ConnectionStrings/IConnectionStringCodec.cs

@@ -0,0 +1,19 @@
+using FluentResults;
+
+namespace pgLabII.PgUtils.ConnectionStrings;
+
+/// <summary>
+/// Codec for a specific connection string format (parse and format only for its own format).
+/// Do not implement format specifics yet; provide interface only.
+/// </summary>
+public interface IConnectionStringCodec
+{
+    ConnStringFormat Format { get; }
+    string FormatName { get; }
+
+    // Parse input in this codec's format into a descriptor.
+    Result<ConnectionDescriptor> TryParse(string input);
+
+    // Format a descriptor into this codec's format.
+    Result<string> TryFormat(ConnectionDescriptor descriptor);
+}