fix: use ExUnit exclude mechanism for Deno test skipping

- Replace setup block with ExUnit's exclude mechanism for conditional test skipping
- Add :skip_if_no_deno tag to Deno runtime integration tests
- Configure test_helper.exs to exclude :skip_if_no_deno tests when Deno is not available
- This follows ExUnit best practices for conditional test execution

Resolves CI test failures by properly skipping Deno tests when Deno executable is missing.

Author: GSMLG-BOT

test/phoenix/react/runtime_integration_test.exs

@@ -81,14 +81,7 @@ defmodule Phoenix.React.RuntimeIntegrationTest do
 
   describe "Deno Runtime Integration" do
     @describetag :deno_runtime
-
-    setup do
-      if System.find_executable("deno") == nil do
-        {:skip, "Deno not available"}
-      else
-        :ok
-      end
-    end
+    @describetag :skip_if_no_deno
 
     test "configuration validation" do
       # Test valid configuration

test/test_helper.exs

@@ -1,4 +1,12 @@
-ExUnit.start()
+# Configure ExUnit to skip Deno tests if Deno is not available
+exclude =
+  if System.find_executable("deno") == nil do
+    [:skip_if_no_deno]
+  else
+    []
+  end
+
+ExUnit.start(exclude: exclude)
 Phoenix.React.start_link([])
 
 ExUnit.after_suite(fn _results ->