Tell agents not to use inline qualified names

Summary:
We use IDE settings to enforce this, and we try to catch it as a nit
on code review, but I realized we're actually never telling agents
about it which is likely part of why they periodically use qualified
names.

Reviewed By: ndmitchell

Differential Revision: D92972130

fbshipit-source-id: a2ad76cae0029192b39fc33d9a8dff610f04b65b

Author: stroxler

AGENTS.md

@@ -63,6 +63,10 @@ Coding style: All code must be clean, documented and minimal. That means:
 - Minimize the number of places `Expr` nodes are passed around and the number of
   times they are parsed. Generally, this means extracting semantic information
   as early as possible.
+- **Imports:** Always add `use` imports at the top of the file rather than using
+  inline qualified paths (e.g., write `use crate::foo::Bar;` and then `Bar`,
+  not `crate::foo::Bar` inline). The only exception is when there is a name
+  collision between two imports, which is rare.
 
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