v1.0.0: Route constraint for device slugs

Routing/DeviceSlugConstraint.cs

@@ -0,0 +1,28 @@
+using NoticeBoard.Data;
+using Microsoft.EntityFrameworkCore;
+
+namespace NoticeBoard.Routing;
+
+public class DeviceSlugConstraint : IRouteConstraint
+{
+    // Reserved paths that should NOT be treated as device slugs
+    private static readonly HashSet<string> ReservedPaths = new(StringComparer.OrdinalIgnoreCase)
+    {
+        "admin", "api", "d", "error", "css", "js", "lib", "uploads", "favicon.ico"
+    };
+
+    public bool Match(HttpContext? httpContext, IRouter? route, string routeKey,
+        RouteValueDictionary values, RouteDirection routeDirection)
+    {
+        if (values.TryGetValue(routeKey, out var value) && value is string slug)
+        {
+            // Block reserved paths
+            if (ReservedPaths.Contains(slug))
+                return false;
+
+            // Only match lowercase alphanumeric + hyphens
+            return slug.All(c => char.IsLetterOrDigit(c) || c == '-');
+        }
+        return false;
+    }
+}