Add SSL, MDC database, and custom HANA connection parameters

Fixes 'error while parsing protocol' HanaException by supporting
SSL/TLS encryption, Multi-Tenant Database Container (MDC) database
name, and arbitrary additional connection parameters.

- HanaServer model: added DatabaseName, UseSsl, ValidateCertificate,
  AdditionalParams fields + BuildConnectionString() helper
- HanaQueryService: accepts HanaServer directly, uses
  BuildConnectionString() for full parameter support
- AppDbContext: added EnsureSchema() method that uses PRAGMA table_info
  + ALTER TABLE ADD COLUMN to add the new fields to existing SQLite
  databases without losing data (EnsureCreated does not update schema)
- Program.cs: calls EnsureSchema on startup before seeding
- Standorte.razor: server dialog now exposes DatabaseName, UseSsl,
  ValidateCertificate, AdditionalParams with helper texts; test
  connection uses new signature

https://claude.ai/code/session_012heAXNMbbyxqYf2S2HrKLj

TrafagSalesExporter/Models/HanaServer.cs

@@ -17,4 +17,49 @@ public class HanaServer
     public string Username { get; set; } = string.Empty;
 
     public string Password { get; set; } = string.Empty;
+
+    /// <summary>
+    /// Name der Tenant-Datenbank bei Multi-Tenant Database Container (MDC) Setups.
+    /// Leer lassen, wenn direkt auf einen Tenant-Port verbunden wird.
+    /// </summary>
+    public string DatabaseName { get; set; } = string.Empty;
+
+    /// <summary>
+    /// SSL/TLS Verschlüsselung aktivieren (encrypt=true).
+    /// </summary>
+    public bool UseSsl { get; set; }
+
+    /// <summary>
+    /// SSL-Zertifikat validieren. Bei self-signed Zertifikaten auf false setzen.
+    /// </summary>
+    public bool ValidateCertificate { get; set; }
+
+    /// <summary>
+    /// Zusätzliche Verbindungsparameter (Semikolon-getrennt), z.B. "sslCryptoProvider=openssl".
+    /// </summary>
+    public string AdditionalParams { get; set; } = string.Empty;
+
+    public string BuildConnectionString()
+    {
+        var parts = new List<string>
+        {
+            $"ServerNode={Host}:{Port}",
+            $"UserName={Username}",
+            $"Password={Password}"
+        };
+
+        if (!string.IsNullOrWhiteSpace(DatabaseName))
+            parts.Add($"DatabaseName={DatabaseName}");
+
+        if (UseSsl)
+        {
+            parts.Add("encrypt=true");
+            parts.Add($"sslValidateCertificate={(ValidateCertificate ? "true" : "false")}");
+        }
+
+        if (!string.IsNullOrWhiteSpace(AdditionalParams))
+            parts.Add(AdditionalParams.Trim().Trim(';'));
+
+        return string.Join(";", parts);
+    }
 }