Add admin page to list and revoke Micropub tokens

Gives a way to actually use the revocation capability built up over
the last few commits from the admin side, not just self-service via
the client. Lists client_id/scope/issue time per token (never the raw
token itself, since only its hash is stored) with a revoke button for
active ones.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_014625MfkGZ7GVdbqKme4a8L

resources/views/admin/welcome.blade.php

@@ -47,6 +47,11 @@
         or <a href="/admin/syndication">edit</a> them.
     </p>
 
+    <h2>Tokens</h2>
+    <p>
+        View and <a href="/admin/tokens">revoke</a> issued Micropub tokens.
+    </p>
+
     <h2>Bio</h2>
     <p>
         Edit your <a href="/admin/bio">bio</a>.