Website: contribute page, Discord/Forgejo links, nav update, security cleanup

- New contribute.html with honest project story and contributor guide
- Discord and Contribute links added to nav on all pages
- Forgejo + Discord links in all footers
- Removed sensitive data from project-notes (passwords, server paths)
- Updated .gitignore to exclude keystores, APKs, AppImages, credentials

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

website/index.html

@@ -15,6 +15,8 @@
             <a href="tech.html">How It Works</a>
             <a href="design.html">Design</a>
             <a href="download.html">Download</a>
+            <a href="contribute.html">Contribute</a>
+            <a href="https://discord.gg/pCjMbY9PmN">Discord</a>
         </div>
     </nav>
 
@@ -123,13 +125,17 @@
 
         <section>
             <h2>Get involved</h2>
-            <p>ItsGoin is open source and always will be.</p>
-            <p><a href="download.html">Download the app</a> &middot; <a href="tech.html">Read the technical overview</a> &middot; <a href="design.html">Explore the design document</a></p>
+            <p>ItsGoin is open source and always will be. Built by a network tech guy vibe-coding beyond his abilities with AI &mdash; and it works. But it could use your help to get even better.</p>
+            <p style="margin-top: 0.75rem;">
+                <a href="download.html" class="btn btn-primary" style="margin-right: 0.5rem;">Download the app</a>
+                <a href="https://discord.gg/pCjMbY9PmN" class="btn btn-secondary" style="margin-right: 0.5rem;">Join the Discord</a>
+                <a href="https://git.itsgoin.net/Sologretto/itsgoin" class="btn btn-secondary">Browse the code</a>
+            </p>
         </section>
     </div>
 
     <footer>
-        <p>ItsGoin &mdash; Apache 2.0 License &mdash; <a href="https://itsgoin.com">itsgoin.com</a></p>
+        <p>ItsGoin &mdash; Apache 2.0 License &mdash; <a href="https://itsgoin.com">itsgoin.com</a> &middot; <a href="https://discord.gg/pCjMbY9PmN">Discord</a> &middot; <a href="https://git.itsgoin.net/Sologretto/itsgoin">Source Code</a></p>
     </footer>
 </body>
 </html>