feat: edit existing model entries in the Model Registry

- Inline edit form per model row (label, model name/ID, host/account, context, tags)
- Fetch models button in edit form for local models — same live-picker UX as Add Model
- POST /settings/local/models/{id}/edit route in local_llm.py
- Admin role badge (ADMIN/USER pill) in Account Settings page
- HELP.md updated: new tools table with admin/confirm markers, PWA install section
- TODO updated: tool expansions marked done, distill review and Unsloth resolved,
  role-based access and admin badge added to completed

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

cortex/routers/settings.py

@@ -60,6 +60,9 @@ def _settings_page(username: str, personas: list[str], back_persona: str = "", s
     google_email = auth_data.get("google_email") or ""
     html = html.replace("{{ google_email }}", google_email)
 
+    role = auth_data.get("role", "user")
+    html = html.replace("{{ user_role }}", role)
+
     persona_items = "\n".join(
         f'''<li>
           <a href="/{username}/{p}" class="persona-link">{p}</a>