feat(phase-17): Vararg expansion, scope fixes, and suite triage (#141)

Co-authored-by: Dave Lucia <dave@dave-mac-mini.tail23398.ts.net>
Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

Author: 3 people

AGENTS.md

@@ -115,6 +115,7 @@ mix usage_rules.search_docs "Enum.zip" --query-by title
 ## Debugging
 
 - Use `dbg/1` to print values while debugging. This will display the formatted value and other relevant information in the console.
+- Write ExUnit tests when trying to replicate bugs or issues. DO NOT use mix run -e unless necessary, always try to write a unit test replicating failures first.
 
 <!-- usage_rules:elixir-end -->
 <!-- usage_rules:otp-start -->