ref(coding-agents): consolidate into single agents.md (#104550)

Cursor's support of nested AGENTS.md files seems to not be working.
https://forum.cursor.com/t/nested-agents-md-files-not-being-loaded/138411/8

in the meantime, let's just consolidate into the root static.md. can
re-evaluate if this causes issues.

Author: JoshFerge