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/Program.cs

@@ -27,6 +27,7 @@ using (var scope = app.Services.CreateScope())
     var dbFactory = scope.ServiceProvider.GetRequiredService<IDbContextFactory<AppDbContext>>();
     using var db = await dbFactory.CreateDbContextAsync();
     await db.Database.EnsureCreatedAsync();
+    AppDbContext.EnsureSchema(db);
     AppDbContext.SeedIfEmpty(db);
 }