feat: showcase facing states in poker setup

Deal the deck facedown and stand two drawn cards on their bottom edge,
exercising the back and standing facings alongside the face-up flop.

games/poker/poker.md

@@ -125,8 +125,9 @@ string,number,number,number
 
 ## Setup
 
-Deal the whole deck onto the draw pile (`poker:card` expands to every card of
-that type), then flip a flop onto the community slots.
+Deal the whole deck facedown onto the draw pile (`poker:card` expands to every
+card of that type, `facing: back`), then flip a flop onto the community slots
+and stand a couple of drawn cards on their bottom edge.
 
 ```yaml file=main.yaml
 role: setup
@@ -135,10 +136,17 @@ id: main
 setup:
   - path: /deck
     parts: poker:card
+    facing: back
   - path: /community/0
     parts: poker:card#as
   - path: /community/1
     parts: poker:card#kh
   - path: /community/2
     parts: poker:card#7d
+  - path: /community/3
+    parts: poker:card#jc
+    facing: standing
+  - path: /community/4
+    parts: poker:card#2h
+    facing: standing
 ```