Simplify EventHub diagram: merge ScadaBridge + store-and-forward

outputs/diagrams/redpanda-eventhub.mmd

@@ -1,16 +1,9 @@
 flowchart LR
-    subgraph Sites["Site ScadaBridge Clusters"]
-        SB1["ScadaBridge<br/>Warsaw West"]
-        SB2["ScadaBridge<br/>Shannon"]
-        SB3["ScadaBridge<br/>Ponce"]
-        SBN["ScadaBridge<br/>... other sites"]
-    end
-
-    subgraph SAF["Store & Forward<br/>(per site, per call)"]
-        Q1["Local Queue"]
-        Q2["Local Queue"]
-        Q3["Local Queue"]
-        QN["Local Queue"]
+    subgraph Sites["Site ScadaBridge Clusters (with Store & Forward)"]
+        SB1["ScadaBridge — Warsaw West<br/>+ local queue"]
+        SB2["ScadaBridge — Shannon<br/>+ local queue"]
+        SB3["ScadaBridge — Ponce<br/>+ local queue"]
+        SBN["ScadaBridge — other sites<br/>+ local queue"]
     end
 
     subgraph Redpanda["Redpanda Central Cluster (South Bend)"]
@@ -33,10 +26,10 @@ flowchart LR
         REPLAY["Historical Replay<br/>(simulation-lite)"]
     end
 
-    SB1 --> Q1 --> T1
-    SB2 --> Q2 --> T2
-    SB3 --> Q3 --> T3
-    SBN --> QN --> T4
+    SB1 --> T1
+    SB2 --> T2
+    SB3 --> T3
+    SBN --> T4
     SR -.->|"validates"| Topics
     AUTH -.->|"enforces"| Topics
     T1 --> SNB