feat: add SiteNotificationRepository and SMTP storage

src/ScadaLink.SiteRuntime/Persistence/SiteStorageService.cs

@@ -77,6 +77,18 @@ public class SiteStorageService
                 recipient_emails     TEXT NOT NULL,
                 updated_at           TEXT NOT NULL
             );
+
+            CREATE TABLE IF NOT EXISTS smtp_configurations (
+                name                 TEXT PRIMARY KEY,
+                server               TEXT NOT NULL,
+                port                 INTEGER NOT NULL,
+                auth_mode            TEXT NOT NULL,
+                from_address         TEXT NOT NULL,
+                username             TEXT,
+                password             TEXT,
+                oauth_config         TEXT,
+                updated_at           TEXT NOT NULL
+            );
         ";
         await command.ExecuteNonQueryAsync();
 
@@ -416,6 +428,45 @@ public class SiteStorageService
 
         await command.ExecuteNonQueryAsync();
     }
+
+    // ── WP-33: SMTP Configuration CRUD ──
+
+    /// <summary>
+    /// Stores or updates an SMTP configuration.
+    /// </summary>
+    public async Task StoreSmtpConfigurationAsync(
+        string name, string server, int port, string authMode, string fromAddress,
+        string? username, string? password, string? oauthConfig)
+    {
+        await using var connection = new SqliteConnection(_connectionString);
+        await connection.OpenAsync();
+
+        await using var command = connection.CreateCommand();
+        command.CommandText = @"
+            INSERT INTO smtp_configurations (name, server, port, auth_mode, from_address, username, password, oauth_config, updated_at)
+            VALUES (@name, @server, @port, @authMode, @fromAddress, @username, @password, @oauthConfig, @updatedAt)
+            ON CONFLICT(name) DO UPDATE SET
+                server = excluded.server,
+                port = excluded.port,
+                auth_mode = excluded.auth_mode,
+                from_address = excluded.from_address,
+                username = excluded.username,
+                password = excluded.password,
+                oauth_config = excluded.oauth_config,
+                updated_at = excluded.updated_at";
+
+        command.Parameters.AddWithValue("@name", name);
+        command.Parameters.AddWithValue("@server", server);
+        command.Parameters.AddWithValue("@port", port);
+        command.Parameters.AddWithValue("@authMode", authMode);
+        command.Parameters.AddWithValue("@fromAddress", fromAddress);
+        command.Parameters.AddWithValue("@username", (object?)username ?? DBNull.Value);
+        command.Parameters.AddWithValue("@password", (object?)password ?? DBNull.Value);
+        command.Parameters.AddWithValue("@oauthConfig", (object?)oauthConfig ?? DBNull.Value);
+        command.Parameters.AddWithValue("@updatedAt", DateTimeOffset.UtcNow.ToString("O"));
+
+        await command.ExecuteNonQueryAsync();
+    }
 }
 
 /// <summary>