Add account-wide projected margin ratio helper (#60)

* feat: add account projected margin ratio helper

* Bump version to v0.9.4

* fix: address account margin ratio review feedback

* fix: simplify account margin ratio errors

uv.lock

@@ -487,7 +487,7 @@ wheels = [
 
 [[package]]
 name = "mt5cli"
-version = "0.9.3"
+version = "0.9.4"
 source = { editable = "." }
 dependencies = [
     { name = "click" },