Fix ReadTheDocs build: remove linkify extension

Remove 'linkify' from myst_enable_extensions in docs/conf.py
as it requires the linkify-it-py package which is not installed
in the RTD environment. The linkify extension is not essential
for documentation functionality.

This fixes the RTD build error:
ModuleNotFoundError: Linkify enabled but not installed

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

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

Author: dshkol

docs/conf.py

@@ -79,7 +79,6 @@
     "dollarmath",
     "html_admonition",
     "html_image",
-    "linkify",
     "replacements",
     "smartquotes",
     "substitution",