docs: clarify execution flow

Signed-off-by: Michael Gasch <15986659+embano1@users.noreply.github.com>

Author: embano1

LANGUAGE_SDK_SPECIFICATION.md

@@ -302,13 +302,14 @@ The SDK MUST:
 
 ```mermaid
 flowchart LR
-    New[Customer calls operation] --> START
-    START --> |Started| SUCCEED
+    STARTED[Execution starts] --> |Started| SUCCEED
     SUCCEED --> |Succeeded| Success[Completes successfully]
-    START --> |Started| FAIL
+    STARTED --> |Started| FAIL
     FAIL --> |Failed| Failure[Completes with error]
 ```
 
+Note: The EXECUTION operation is always in STARTED status when the handler begins. It does not have a START action.
+
 ### 4.4 STEP Operation
 
 #### 4.4.1 Purpose