ARCH-001 Phase 16: fix Comments(GET) 500 — redirect instead of rendering nonexistent view

Copilot review on PR #810: BaseNewsController.Comments(string) returned View()
but no Comments.cshtml exists for News (unlike Blog, which has one). Preexisting
bug carried over from Admin's original NewsController, verified against the
merge-base. The GET action is unreachable via the UI — the Comments tab's grid
calls the POST overload only — so redirect to List instead of leaving a dead
View() call that 500s if ever hit directly.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01FRztBQVfXimBPMFAioLabo

Author: KrzysztofPajak

src/Web/Grand.Web.AdminShared/Controllers/BaseNewsController.cs

@@ -171,11 +171,11 @@ public async Task<IActionResult> Delete(string id)
 
     #region Comments
 
-    public IActionResult Comments(string filterByNewsItemId)
-    {
-        ViewBag.FilterByNewsItemId = filterByNewsItemId;
-        return View();
-    }
+    // Ruled fix (PR review): Admin's original returned View() here with no Comments.cshtml ever
+    // existing for News (unlike Blog, which has one) - a preexisting 500 if this GET were ever hit
+    // directly. Unreachable from the UI (the Comments tab's grid calls the POST overload only), so
+    // redirect instead of carrying the dead View() call forward.
+    public IActionResult Comments(string filterByNewsItemId) => RedirectToAction("List");
 
     [PermissionAuthorizeAction(PermissionActionName.List)]
     [HttpPost]