feat(ui): link the Created By cell on the Prompts page (#40753)

The column was plain muted text, so finding out who owns a prompt meant
copying the id into the Users page search box. Route it through
IdentityCell with userDetailHref, which keeps the proxy admin placeholder
unlinked.

Claude-Session: https://claude.ai/code/session_01NfwfQhamRNnSqgXMUjf3h4

ui/litellm-dashboard/src/app/(dashboard)/prompts/_components/PromptTable.test.tsx

@@ -10,6 +10,8 @@ vi.mock("@/components/networking", () => ({
   modelHubCall: vi.fn().mockResolvedValue({ data: [] }),
 }));
 
+vi.mock("next/navigation", () => ({ useRouter: () => ({ push: vi.fn() }) }));
+
 const mockPrompts: PromptSpec[] = [
   {
     prompt_id: "prompt-newer",
@@ -53,6 +55,15 @@ describe("PromptTable", () => {
     }
   });
 
+  it("links the Created By cell to the creator's detail page, leaving the placeholder unlinked", () => {
+    const prompts = [mockPrompts[0], { ...mockPrompts[1], created_by: "default_user_id" }];
+    render(<PromptTable {...defaultProps} promptsList={prompts} />);
+
+    expect(screen.getByRole("link", { name: "user-1" })).toHaveAttribute("href", "/ui/users?user=user-1");
+    expect(screen.getByText("default_user_id")).toBeInTheDocument();
+    expect(screen.queryByRole("link", { name: "default_user_id" })).not.toBeInTheDocument();
+  });
+
   it("should display the empty state when data is empty", () => {
     render(<PromptTable {...defaultProps} promptsList={[]} />);
     expect(screen.getByText("No prompts yet")).toBeInTheDocument();

ui/litellm-dashboard/src/app/(dashboard)/prompts/_components/PromptTableColumns.tsx

@@ -17,6 +17,7 @@ import {
 } from "@/components/ui/dropdown-menu";
 import { cn } from "@/lib/cva.config";
 import { copyToClipboard } from "@/utils/dataUtils";
+import { userDetailHref } from "@/utils/entityLinks";
 
 import { extractModel, getProviderFromModelHub, ModelGroupInfo } from "./prompt_utils";
 
@@ -191,9 +192,16 @@ export const getPromptTableColumns = ({
     enableSorting: false,
     cell: ({ row }) => {
       const createdBy = row.original.created_by;
+      if (!createdBy) {
+        return <span className="text-muted-foreground">-</span>;
+      }
       return (
-        <span className="block max-w-60 truncate text-sm text-muted-foreground" title={createdBy}>
-          {createdBy || "-"}
+        <span className="block max-w-60" title={createdBy}>
+          <IdentityCell
+            title={createdBy}
+            titleClassName="font-normal text-muted-foreground"
+            href={userDetailHref(createdBy)}
+          />
         </span>
       );
     },