Fix issues with Journal handling

Implement basic database
Handle startup events
only send events after the most recent LoadGame

Pulsar/Features/NavRoute/NavRouteService.cs

@@ -0,0 +1,46 @@
+namespace Pulsar.Features.NavRoute;
+
+using Observatory.Framework.Files;
+
+public interface INavRouteService :  IJournalHandler<NavRouteFile>;
+
+public class NavRouteService(IOptions<PulsarConfiguration> options, ILogger<NavRouteService> logger, IEventHubContext hub) : INavRouteService
+{
+    public async Task<NavRouteFile> Get()
+    {
+        var navRouteFile = Path.Combine(options.Value.JournalDirectory, FileName);
+
+        if (!FileHelper.ValidateFile(navRouteFile))
+        {
+            return new NavRouteFile();
+        }
+
+        await using var file = File.Open(navRouteFile, FileMode.Open, FileAccess.Read, FileShare.ReadWrite);
+        var shipLocker = await JsonSerializer.DeserializeAsync<NavRouteFile>(file);
+        if (shipLocker != null) return shipLocker;
+
+        logger.LogWarning("Failed to deserialize nav route file {ShipLockerFile}", navRouteFile);
+        return new NavRouteFile();
+    }
+
+    public async Task HandleFile(string path, CancellationToken token = new ())
+    {
+        if (!FileHelper.ValidateFile(path))
+        {
+            return;
+        }
+
+        var file = File.Open(path, FileMode.Open, FileAccess.Read, FileShare.ReadWrite);
+        var navRoute = await JsonSerializer.DeserializeAsync<NavRouteFile>(file, cancellationToken: token);
+
+        if (navRoute == null)
+        {
+            logger.LogWarning("Failed to deserialize nav route {FilePath}", file);
+            return;
+        }
+
+        await hub.Clients.All.NavRouteUpdated(navRoute);
+    }
+
+    public string FileName => FileHandlerService.NavRouteFileName;
+}