chore: refresh openapi.json for the widened expire_after schema

The backend now declares expire_after as string or epoch integer on
create, update and bulk expiry, matching what its validator always
accepted. No generated code in this repo; the vendored spec is the
drift-check baseline.

Author: Zingzy

openapi.json

@@ -9592,6 +9592,9 @@
                 "type": "string",
                 "format": "date-time"
               },
+              {
+                "type": "integer"
+              },
               {
                 "type": "null"
               }
@@ -10143,6 +10146,9 @@
                 "type": "string",
                 "format": "date-time"
               },
+              {
+                "type": "integer"
+              },
               {
                 "type": "null"
               }
@@ -12826,6 +12832,9 @@
                 "type": "string",
                 "format": "date-time"
               },
+              {
+                "type": "integer"
+              },
               {
                 "type": "null"
               }