OpenFlow sleep runs after its module, not before (#12074)

The worker schedules step i after the sleep of module i-1
(worker_flow.rs), so a module's sleep delays the step after it. The
schema said "Delay before executing this step", and that text reaches
the write-flow skill, the flow chat and the MCP session instructions.

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

backend/windmill-api/openapi-deref.json

@@ -35080,7 +35080,7 @@
             ]
           },
           "sleep": {
-            "description": "Delay before executing this step (in seconds or as expression)",
+            "description": "Delay after this step completes, before the next step starts (in seconds or as expression)",
             "$ref": "#/components/schemas/schemas-InputTransform"
           },
           "cache_ttl": {
@@ -47034,7 +47034,7 @@
             ]
           },
           "sleep": {
-            "description": "Delay before executing this step (in seconds or as expression)",
+            "description": "Delay after this step completes, before the next step starts (in seconds or as expression)",
             "$ref": "#/components/schemas/schemas-InputTransform"
           },
           "cache_ttl": {

openflow.openapi.yaml

@@ -308,7 +308,7 @@ components:
           required:
             - expr
         sleep:
-          description: Delay before executing this step (in seconds or as expression)
+          description: Delay after this step completes, before the next step starts (in seconds or as expression)
           $ref: '#/components/schemas/InputTransform'
         cache_ttl:
           type: number