docs(site): add remote-access (Tailscale/Cloudflare/ngrok) and honest iOS pages

New high-intent SEO pages:
- /remote-access/ — step-by-step Tailscale, Cloudflare Tunnel, ngrok setups
  for reaching a self-hosted opencode server from Android anywhere. HowTo +
  FAQ + BreadcrumbList structured data.
- /ios/ — honest 'no iOS app yet' page: current Android app, why, options,
  roadmap, how to follow. FAQ + BreadcrumbList structured data.

Added to sitemap.xml; internal links from index, guide, opencode-on-phone,
and troubleshooting.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

docs-site/opencode-on-phone/index.html

@@ -287,6 +287,7 @@ footer a{margin:0 8px}
       OpenCode Mobile stores credentials in the Android Keystore, and you can require biometric unlock
       before each send.
     </div>
+    <p style="margin-top:14px">For step-by-step instructions on each method, see <a href="../remote-access/">access opencode from your phone remotely</a>.</p>
   </div>
 </section>
 
@@ -350,6 +351,7 @@ footer a{margin:0 8px}
       <a href="../">Home</a>
       <a href="../guide/">Setup guide</a>
       <a href="../download/">Download</a>
+      <a href="../remote-access/">Remote access</a>
       <a href="../vs-termux/">vs Termux</a>
       <a href="../troubleshooting/">Troubleshooting</a>
       <a href="https://github.com/dzianisv/opencode-mobile">GitHub</a>