Add missing file

backend/FwHeadless/Services/HttpHelpers.cs

@@ -0,0 +1,14 @@
+namespace FwHeadless.Services;
+
+public static class HttpHelpers
+{
+    public static Guid? GetProjectId(this HttpContext? context)
+    {
+        if (context is null) return null;
+        if (context.Request.Query.TryGetValue("projectId", out var projectIds) && projectIds.FirstOrDefault() is string idStr)
+        {
+            if (Guid.TryParse(idStr, out var projectId)) return projectId;
+        }
+        return null;
+    }
+}