Enable auto-login for PTD products

In our Posit Team Snowflake Native Application which runs all the products we recently switched to OIDC. This switch however made all products require a login page like

We implemented a "fix" for this on the landing page and inside workbench in https://github.com/rstudio/partnership-snowflake/pull/1492/commits/547665679d7a048cd304e42f5a326b38fd32cdd8.

Basically for connect and package-manager use /__login__?url=/ in the landing page which will force login and redirect to the home page.

For workbench we inject html into the login page to automatically click buttons for them.

auth-login-page-html=/etc/rstudio/rstudio-login.html

<script>
  // 1. ensure checkbox is checked to remember login
  // 2. submit the OIDC login form with 100ms delay
  window.addEventListener('DOMContentLoaded', function() {
      const checkbox = document.getElementById('staySignedIn');
      if (checkbox) {
          checkbox.checked = true;
      }

      const form = document.forms['login_form'];
      if (form) {
          setTimeout(function() {
              form.submit();
          }, 100); // 100ms delay
      }
  });
</script>

Start by reviewing the landing page and workbench entry points, along with the referenced partnership-snowflake commit. Check how /__login__?url=/, auth-login-page-html, and /etc/rstudio/rstudio-login.html are used; done means PTD products automatically authenticate and redirect without requiring manual login-page interaction.