docs(formatter): note collapsed Tailwind templates in member chain layouts

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

crates/oxc_formatter/AGENTS.md

@@ -60,6 +60,9 @@ After changing AST shapes or the generators, regenerate with `just ast`, never h
 - Covered by the Oxfmt API tests (`apps/oxfmt/test/api/sort_tailwindcss.test.ts`), since only the host sorts
 - Deliberately unlike the plugin, nothing in the arguments of a nested non-Tailwind call is sorted
   (tailwindlabs/prettier-plugin-tailwindcss#426): `cn(x.includes("a  b"))` keeps `"a  b"`, which the plugin rewrites
+- Known limitation, left since the triggers are rare and a fix would thread Tailwind state through `SimpleArgument`:
+  a multiline template collapsed by sorting is still judged by its source line breaks in some layouts,
+  so a Tailwind call with one inside a member chain can take a second pass to settle
 
 ### Embedded language formatting