fix(database): qualify RD21 saves against pinned MariaDB 12.2.2

JobTrackerApi/Services/DatabaseBackupRunner.cs

@@ -1,4 +1,5 @@
 using Microsoft.Data.Sqlite;
+using JobTrackerApi.Data;
 
 namespace JobTrackerApi.Services
 {
@@ -28,15 +29,8 @@ namespace JobTrackerApi.Services
         {
             _logger = logger;
 
-            var provider = (cfg["Database:Provider"] ?? "sqlite").Trim().ToLowerInvariant();
-            var cs = cfg.GetConnectionString("JobTracker");
-            if (string.IsNullOrWhiteSpace(cs))
-            {
-                cs = $"Data Source={paths.GetDbPath()}";
-                provider = "sqlite";
-            }
-
-            _connectionString = cs;
+            var provider = DatabaseConfiguration.GetProvider(cfg);
+            _connectionString = DatabaseConfiguration.GetConnectionString(cfg, paths.GetDbPath());
             IsSupported = provider == "sqlite";
             BackupsRoot = Path.Combine(paths.DataRoot, "backups");
             _retainCount = Math.Clamp(cfg.GetValue("Backups:RetainCount", 14), 1, 365);