feat: apikey alias field + markdown/patch authorship display

- ApiKeyCreationModal: required Alias input (reuse alias = renew, with
  banner); align roles to backend allowlist (guest -> user, default
  user); fix copy bug (generatedKey.key).
- MarkdownContent + PatchCards: show author / created / last modified
  (+ by whom); formatDateTime helper (null -> "—").

Branched off fix/buildconfig-cachebust (carries the contenthash +
BuildConfig fix already deployed to prod).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/components/Markdowns/MarkdownContent.js

@@ -2,7 +2,8 @@ import React, { useEffect, useState } from "react";
 import {Link, useParams} from "react-router-dom";
 import "katex/dist/katex.min.css";
 import "./MarkdownContent.css";
-import { Settings2, Pencil } from "lucide-react";
+import { Settings2, Pencil, User, Clock, History } from "lucide-react";
+import { formatDateTime } from "../../lib/utils";
 import MarkdownView from "./MarkdownView";
 import PatchCards from "./PatchCards";
 import PermissionGuard from "../PermissionGuard";
@@ -85,6 +86,23 @@ const MarkdownContent = () => {
                     </div>
                 </PermissionGuard>
             </div>
+            <div className="-mt-3 mb-6 flex flex-wrap items-center gap-x-5 gap-y-1 font-mono text-xs text-muted-foreground">
+                <span className="inline-flex items-center gap-1.5">
+                    <User className="h-3.5 w-3.5 text-secondary" />
+                    {markdown.author || "—"}
+                </span>
+                <span className="inline-flex items-center gap-1.5">
+                    <Clock className="h-3.5 w-3.5" />
+                    created {formatDateTime(markdown.created_at)}
+                </span>
+                <span className="inline-flex items-center gap-1.5">
+                    <History className="h-3.5 w-3.5" />
+                    updated {formatDateTime(markdown.updated_at)}
+                    {markdown.last_modified_by
+                        ? ` by ${markdown.last_modified_by}`
+                        : ""}
+                </span>
+            </div>
             <MarkdownView content={parseMarkdownContent(markdown.content)} template={template}/>
             <PatchCards markdownId={id} />
             <MarkdownSettingModal