feat(eidas): Implement eIDAS Crypto Plugin with dependency injection and signing capabilities

- Added ServiceCollectionExtensions for eIDAS crypto providers.
- Implemented EidasCryptoProvider for handling eIDAS-compliant signatures.
- Created LocalEidasProvider for local signing using PKCS#12 keystores.
- Defined SignatureLevel and SignatureFormat enums for eIDAS compliance.
- Developed TrustServiceProviderClient for remote signing via TSP.
- Added configuration support for eIDAS options in the project file.
- Implemented unit tests for SM2 compliance and crypto operations.
- Introduced dependency injection extensions for SM software and remote plugins.

src/__Libraries/StellaOps.Cryptography.Plugin.EIDAS/DependencyInjection/ServiceCollectionExtensions.cs

@@ -0,0 +1,51 @@
+// SPDX-License-Identifier: AGPL-3.0-or-later
+// Sprint: SPRINT_4100_0006_0002 - eIDAS Crypto Plugin
+
+using Microsoft.Extensions.Configuration;
+using Microsoft.Extensions.DependencyInjection;
+using StellaOps.Cryptography;
+using StellaOps.Cryptography.Plugin.EIDAS.Configuration;
+
+namespace StellaOps.Cryptography.Plugin.EIDAS.DependencyInjection;
+
+/// <summary>
+/// Dependency injection extensions for eIDAS crypto plugin.
+/// </summary>
+public static class ServiceCollectionExtensions
+{
+    /// <summary>
+    /// Add eIDAS crypto providers to the service collection.
+    /// </summary>
+    public static IServiceCollection AddEidasCryptoProviders(
+        this IServiceCollection services,
+        IConfiguration configuration)
+    {
+        // Bind eIDAS configuration
+        services.Configure<EidasOptions>(configuration.GetSection("StellaOps:Crypto:Profiles:eidas"));
+
+        // Register eIDAS components
+        services.AddSingleton<LocalEidasProvider>();
+        services.AddHttpClient<TrustServiceProviderClient>();
+
+        // Register crypto provider
+        services.AddSingleton<ICryptoProvider, EidasCryptoProvider>();
+
+        return services;
+    }
+
+    /// <summary>
+    /// Add eIDAS crypto providers with explicit options.
+    /// </summary>
+    public static IServiceCollection AddEidasCryptoProviders(
+        this IServiceCollection services,
+        Action<EidasOptions> configureOptions)
+    {
+        services.Configure(configureOptions);
+
+        services.AddSingleton<LocalEidasProvider>();
+        services.AddHttpClient<TrustServiceProviderClient>();
+        services.AddSingleton<ICryptoProvider, EidasCryptoProvider>();
+
+        return services;
+    }
+}