Add stream created datetime to StreamInfo

The field is already exposed by NATS "$JS.API.STREAM.INFO.{name}" API: https://nats-io.github.io/nats.js/jetstream/types/StreamInfo.html

Since it's official part of protocol, let's expose it to the user.
Golang implementation already do so: https://github.com/nats-io/nats.go/blob/4ec2f446e4cd829a7be3bf9aa16c43a7fddeaed9/jetstream/stream_config.go#L32

Example API response:
```json
{
  "type": "io.nats.jetstream.api.v1.stream_info_response",
  "total": 0,
  "offset": 0,
  "limit": 0,
  "created": "2025-11-02T15:34:21.730004852Z",
  "config": {
    "name": "stream",
    "subjects": [
      "test.>"
    ],
    "retention": "limits",
    "max_consumers": -1,
    "max_msgs": -1,
    "max_bytes": 2147483648,
    "max_age": 86400000000000,
    "max_msgs_per_subject": -1,
    "max_msg_size": -1,
    "discard": "old",
    "storage": "file",
    "num_replicas": 1,
    "duplicate_window": 120000000000,
    "compression": "s2",
    "allow_direct": false,
    "mirror_direct": false,
    "sealed": false,
    "deny_delete": false,
    "deny_purge": false,
    "allow_rollup_hdrs": false,
    "consumer_limits": {}
  },
  "state": {
    "messages": 1249954,
    "bytes": 1036040689,
    "first_seq": 3326784,
    "first_ts": "2025-11-03T08:38:40.571255423Z",
    "last_seq": 4576737,
    "last_ts": "2025-11-03T13:34:30.52654449Z",
    "num_subjects": 2,
    "consumer_count": 1
  },
  "cluster": {
    "leader": "nats-0"
  },
  "ts": "2025-11-03T13:34:30.530396449Z"
}
```

Author: mathewcohle

nats/src/nats/js/api.py

@@ -410,6 +410,7 @@ class StreamInfo(Base):
     sources: Optional[List[StreamSourceInfo]] = None
     cluster: Optional[ClusterInfo] = None
     did_create: Optional[bool] = None
+    created: Optional[datetime.datetime] = None
 
     @classmethod
     def from_response(cls, resp: Dict[str, Any]):
@@ -418,6 +419,10 @@ def from_response(cls, resp: Dict[str, Any]):
         cls._convert(resp, "mirror", StreamSourceInfo)
         cls._convert(resp, "sources", StreamSourceInfo)
         cls._convert(resp, "cluster", ClusterInfo)
+
+        if "created" in resp and resp["created"]:
+            resp["created"] = datetime.datetime.fromisoformat(resp["created"]).astimezone(datetime.timezone.utc)
+
         return super().from_response(resp)
 
 

nats/tests/test_js.py

@@ -1215,6 +1215,7 @@ async def test_stream_management(self):
         assert isinstance(current.config, nats.js.api.StreamConfig)
         assert current.config.name == "hello"
         assert isinstance(current.state, nats.js.api.StreamState)
+        assert isinstance(current.created, datetime.datetime)
 
         # Send messages
         producer = nc.jetstream()