Fix 1 — new user pages 404 (server.py:228):

After registration creates the user's directories, it now calls _write_root_manifest(dd). This rewrites index.json to include the new handle's shard immediately. Since Astro dev re-evaluates getStaticPaths() on every request (reading that file), /u/pres/, /u/pres/stats/, and /u/pres/athlete/ will resolve correctly as soon as the new user navigates there.

  Fix 2 — invites link (athlete/index.astro:33):
  Added an Invites button (top-right, same style as "Edit profile") that starts hidden. When bincio:me fires and me === handle (you're on your own page), the subnav tabs are removed as before AND the invites button is revealed. Other visitors see neither.

bincio/serve/server.py

@@ -229,6 +229,11 @@ async def register(request: Request) -> JSONResponse:
     (dd / handle / "activities").mkdir(parents=True, exist_ok=True)
     (dd / handle / "edits").mkdir(parents=True, exist_ok=True)
 
+    # Update root manifest so the new user's shard is discoverable immediately
+    # (Astro dev re-evaluates getStaticPaths() on each request from this file)
+    from bincio.render.cli import _write_root_manifest
+    _write_root_manifest(dd)
+
     token = create_session(_get_db(), handle)
     resp = JSONResponse({"ok": True, "handle": handle})
     _set_session_cookie(resp, token)

site/src/pages/u/[handle]/athlete/index.astro

@@ -21,6 +21,8 @@ const athleteUrl = `${mergedBase}athlete.json`;
 ---
 <Base title={`@${handle} Athlete — BincioActivity`}>
   <div class="max-w-5xl mx-auto px-4 pt-6 pb-2">
+    <div class="flex items-start justify-between">
+      <div>
         <h1 class="text-2xl font-bold text-white mb-0.5">@{handle}</h1>
         <nav id="profile-subnav" class="flex gap-4 mt-1 mb-6">
           <a href={`${base}u/${handle}/`} class="text-sm text-zinc-400 hover:text-white transition-colors">Feed</a>
@@ -28,11 +30,20 @@ const athleteUrl = `${mergedBase}athlete.json`;
           <a href={`${base}u/${handle}/athlete/`} class="text-sm text-[--accent]">Athlete</a>
         </nav>
       </div>
+      <a id="invites-btn" href={`${base}invites/`}
+        class="hidden mt-1 px-3 py-1.5 text-xs border border-zinc-700 hover:border-zinc-500 text-zinc-400 hover:text-white rounded-md transition-colors">
+        Invites
+      </a>
+    </div>
+  </div>
   <AthleteView {base} {indexUrl} {athleteUrl} client:only="svelte" />
 </Base>
 <script define:vars={{ handle }}>
   function applyMeCheck(me) {
-    if (me === handle) document.getElementById('profile-subnav')?.remove();
+    if (me === handle) {
+      document.getElementById('profile-subnav')?.remove();
+      document.getElementById('invites-btn')?.classList.remove('hidden');
+    }
   }
   if (window.__bincioMe !== undefined) {
     applyMeCheck(window.__bincioMe);