Add Hermes Agent docs feed to the default source set

Hermes Agent (Nous Research) publishes a maintained llms-full.txt covering
the whole docs site. It parses as markdown-full into ~1.17k documents.

Note against substituting the smaller /docs/llms.txt: parse_llms_text routes
any /llms.txt URL to _parse_menu, which indexes link stubs (title plus
description plus canonical URL) rather than page content.

README.md

@@ -110,6 +110,7 @@ The default docs index uses the vendors' content-bearing `llms-full.txt` feeds:
 - OpenAI API docs and reference
 - OpenRouter docs
 - Model Context Protocol docs
+- Hermes Agent docs
 
 Optional profiles live in `config/`:
 

config/sources.default.txt

@@ -6,3 +6,8 @@ https://developers.openai.com/api/docs/llms-full.txt
 https://developers.openai.com/api/reference/llms-full.txt
 https://openrouter.ai/docs/llms-full.txt
 https://modelcontextprotocol.io/llms-full.txt
+
+# Hermes Agent (Nous Research) publishes a maintained full-docs feed. Parses as
+# markdown-full: ~454 sections. Do not substitute /docs/llms.txt -- menu URLs
+# index link stubs (title + description only), not page content.
+https://hermes-agent.nousresearch.com/llms-full.txt