Add Luna.Configuration with TOML-based agent and provider config

Implement configuration system with embedded TOML resources for agent
and provider definitions, custom IConfigurationSource/Provider for
agent and provider options, and DI extension methods. Includes config
models for agents, providers, sessions, and Telegram integration.

Luna.Configuration/Services/Providers/ProviderOptionsConfigurationProvider.cs

@@ -0,0 +1,32 @@
+using System.Reflection;
+using Microsoft.Extensions.Configuration;
+
+namespace Luna.Configuration.Services.Providers;
+
+internal class ProviderOptionsConfigurationProvider(IEnumerable<(string Name, ProviderOptions Options)> providerOptions)
+    : ConfigurationProvider
+{
+    public override void Load()
+    {
+        foreach (var (name, options) in providerOptions)
+        {
+            var keyPrefix = $"Providers:{name}";
+
+            foreach (var property in options.GetType().GetProperties(BindingFlags.Instance | BindingFlags.Public))
+            {
+                var value = property.GetValue(options);
+
+                if (value is string[] array)
+                {
+                    for (var i = 0; i < array.Length; i++)
+                        Data[$"{keyPrefix}:{property.Name}:{i}"] = array[i];
+                }
+                else
+                {
+                    Data[$"{keyPrefix}:{property.Name}"] = value?.ToString();
+                }
+            }
+        }
+    }
+}
+