Add user registration emails + email infrastructure (#150)

* Add email functionality

* Add email template project and rendering service

* Update email template dir structure

* Add email header and footer components for user registration template

* update example env

* Refactor email templates namespace and components

* Format email dir

src/Core/Infrastructure/Infrastructure.Email.Templates/Rendering/EmailTemplateProvider.cs

@@ -0,0 +1,58 @@
+using Infrastructure.Email.Templates.Mail;
+using Microsoft.AspNetCore.Components;
+using Microsoft.AspNetCore.Components.Web;
+using Microsoft.Extensions.Logging;
+
+namespace Infrastructure.Email.Templates.Rendering;
+
+/// <summary>
+/// Service for rendering Razor email templates to HTML using HtmlRenderer.
+/// </summary>
+public class EmailTemplateProvider(
+    IServiceProvider serviceProvider,
+    ILoggerFactory loggerFactory
+) : IEmailTemplateProvider
+{
+    /// <summary>
+    /// Renders the UserRegisteredEmail template with the specified parameters.
+    /// </summary>
+    public async Task<string> RenderUserRegisteredEmailAsync(
+        string username,
+        string confirmationLink
+    )
+    {
+        var parameters = new Dictionary<string, object?>
+        {
+            { nameof(UserRegistration.Username), username },
+            { nameof(UserRegistration.ConfirmationLink), confirmationLink },
+        };
+
+        return await RenderComponentAsync<UserRegistration>(parameters);
+    }
+
+    /// <summary>
+    /// Generic method to render any Razor component to HTML.
+    /// </summary>
+    private async Task<string> RenderComponentAsync<TComponent>(
+        Dictionary<string, object?> parameters
+    )
+        where TComponent : IComponent
+    {
+        await using var htmlRenderer = new HtmlRenderer(
+            serviceProvider,
+            loggerFactory
+        );
+
+        var html = await htmlRenderer.Dispatcher.InvokeAsync(async () =>
+        {
+            var parameterView = ParameterView.FromDictionary(parameters);
+            var output = await htmlRenderer.RenderComponentAsync<TComponent>(
+                parameterView
+            );
+
+            return output.ToHtmlString();
+        });
+
+        return html;
+    }
+}