Fix Hugo theme configuration for CI build

The theme was commented out in hugo.toml, causing the CI build to fail.
Enabled the PaperMod theme using the Go module path format.

🤖 Generated with [Claude Code](https://claude.ai/code)

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

Author: dsp-ant

blog/hugo.toml

@@ -1,7 +1,7 @@
 baseURL = 'https://blog.modelcontextprotocol.io/'
 languageCode = 'en-us'
 title = 'mcp blog'
-#theme = 'PaperMod'
+theme = 'github.com/adityatelange/hugo-PaperMod'
 [pagination]
   pagerSize = 5