blog: add two new posts — DeepSeek V4 Flash on Hermes Agent & meta story about agent writing blog posts

- deepseek-v4-flash-hermes-agent.html: news post about DeepSeek V4 Flash becoming available through Hermes Agent via OpenRouter, pricing comparisons, benchmarks
- how-agent-writes-blog-posts-while-i-sleep.html: behind-the-scenes story about Oliver's agent writing, reviewing with sub-agents, and publishing autonomously
- Both posts reviewed by SEO, copywriter, and brand sub-agents
- CTA buttons fixed to 'Work with your agent' per brand rules
- Sitemap updated with both new URLs
- index.json updated with both entries at top

sitemap.xml

@@ -143,4 +143,17 @@
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     <ns0:priority>0.6</ns0:priority>
   </ns0:url>
-<ns0:url><ns0:loc>https://derez.ai/blog/posts/speed-run-odoo-static-website.html</ns0:loc><ns0:lastmod>2026-06-22</ns0:lastmod><ns0:changefreq>monthly</ns0:changefreq><ns0:priority>0.7</ns0:priority></ns0:url></ns0:urlset>
+<ns0:url><ns0:loc>https://derez.ai/blog/posts/speed-run-odoo-static-website.html</ns0:loc><ns0:lastmod>2026-06-22</ns0:lastmod><ns0:changefreq>monthly</ns0:changefreq><ns0:priority>0.7</ns0:priority></ns0:url>
+  <ns0:url>
+    <ns0:loc>https://derez.ai/blog/posts/deepseek-v4-flash-hermes-agent.html</ns0:loc>
+    <ns0:lastmod>2026-08-29</ns0:lastmod>
+    <ns0:changefreq>monthly</ns0:changefreq>
+    <ns0:priority>0.7</ns0:priority>
+  </ns0:url>
+  <ns0:url>
+    <ns0:loc>https://derez.ai/blog/posts/how-agent-writes-blog-posts-while-i-sleep.html</ns0:loc>
+    <ns0:lastmod>2026-08-29</ns0:lastmod>
+    <ns0:changefreq>monthly</ns0:changefreq>
+    <ns0:priority>0.6</ns0:priority>
+  </ns0:url>
+</ns0:urlset>