graph-store: removed +mop from sur and added test validator for chat

pkg/arvo/app/graph-store.hoon

@@ -140,7 +140,7 @@
         %+  sort  ~(tap by nodes)
         |=  [p=[=index:store *] q=[=index:store *]]
         ^-  ?
-        (lth (lent p.index) (lent q.index))
+        (lth (lent index.p) (lent index.q))
       ::
       ++  add-node-list
         |=  $:  =resource:store

pkg/arvo/mar/graph/validator/chat.hoon

@@ -0,0 +1,11 @@
+/-  graph=graph-store
+|_  [=atom:store =post:store]
+++  grab
+  |%
+  ++  noun
+    |=  [=atom:store =post:store]
+    ^-  [atom:store post:store]
+    ?>  ?=([@ ~] index.post)
+    [atom post]
+  --
+--

pkg/arvo/sur/graph-store.hoon

@@ -1,13 +1,5 @@
 /-  *post
 |%
-++  mop
-  |*  [key=mold value=mold]
-  |=  ord=$-([key key] ?)
-  |=  a=*
-  =/  b  ;;((tree [key=key val=value]) a)
-  ?>  (check-balance:((ordered-map key value) ord) b)
-  b
-::
 +$  graph         ((mop atom node) gth)
 +$  marked-graph  [p=graph q=(unit mark)]
 ::