DeviceHub: /device WS with bearer auth + hello/hello_ack + ping/pong

backend/DeviceHub/DeviceAuth.cs

@@ -0,0 +1,21 @@
+using backend.Data;
+using backend.Devices;
+using Microsoft.EntityFrameworkCore;
+
+namespace backend.DeviceHub;
+
+public class DeviceAuth(AppDbContext db, DeviceTokenService tokens)
+{
+    public async Task<Device?> AuthenticateAsync(string? authHeader, CancellationToken ct)
+    {
+        if (string.IsNullOrEmpty(authHeader)) return null;
+        const string prefix = "Bearer ";
+        if (!authHeader.StartsWith(prefix, StringComparison.Ordinal)) return null;
+        var token = authHeader[prefix.Length..].Trim();
+        if (string.IsNullOrEmpty(token)) return null;
+        var hash = tokens.Hash(token);
+        var device = await db.Devices.Include(d => d.Config)
+            .FirstOrDefaultAsync(d => d.TokenHash == hash && !d.IsRevoked, ct);
+        return device;
+    }
+}