Set ALTCHA to auto-solve on page load

auto="onload" starts the proof-of-work in the background as soon as
the page loads. By the time a user fills out the form it's already
verified — no manual click required.

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

main-site/contact/index.html

@@ -161,6 +161,7 @@
       <div class="field">
         <altcha-widget
           challenge="/api/altcha"
+          auto="onload"
           style="--altcha-color-border: #dbdbdb; --altcha-border-radius: 4px; --altcha-color-text: #363636;"
         ></altcha-widget>
         <p class="help is-danger" id="err-altcha" style="display:none;">Please complete the verification.</p>

main-site/index.html

@@ -221,6 +221,7 @@
     <div class="field">
       <altcha-widget
         challenge="/api/altcha"
+        auto="onload"
         style="--altcha-color-border: #dbdbdb; --altcha-border-radius: 4px; --altcha-color-text: #363636;"
       ></altcha-widget>
       <p class="help is-danger" id="err-altcha" style="display:none;">Please complete the verification.</p>