fix: Enable jetstream endpoint to resolve stream from subject and add error logs

[TiyaBelay]

Description

Previously, when booting a subscriber with a subject and without an explicit stream, messages are not received and no errors were logged. This was because the errors for InvalidStream (when stream is nil) were raised in nats-pure but was not handled in Leopard and just disappeared in the worker pool. By adding the stream lookup and error logs, we can resolve a stream from a subject when creating a new subscriber in rails and have logged errors displayed when subscriber is booted.

Local Testing

Before this change, we only saw the below when stream is not provided, whereas consumer info displayed 2 unprocessed messages:

Container prizepicks-devenv-rails-run-25dab2d3acef Creating
Container prizepicks-devenv-rails-run-25dab2d3acef Created
2026-10-07 14:25:26.534265 I [1:5696] Rails -- REDIS Audit mode is: false
2026-10-07 14:25:26.534309 I [1:5696] Rails -- REDIS Payments mode is: false
2026-10-07 14:25:39.317612 I [1:5696] DemoEventsSubscriber -- Booting NATS API server...
2026-10-07 14:25:39.317689 I [1:5696] DemoEventsSubscriber -- Building 2 workers with options: {name: "demo-events-subscriber", version: "1.0.0"}, instance_args:
2026-10-07 14:25:39.317864 I [1:5696] DemoEventsSubscriber -- Setting up signal trap...

With this change and stream is not provided, stream is resolved from the subject:

Container prizepicks-devenv-rails-run-25dab2d3acef Creating
Container prizepicks-devenv-rails-run-25dab2d3acef Created
2026-10-07 14:25:26.534265 I [1:5696] Rails -- REDIS Audit mode is: false
2026-10-07 14:25:26.534309 I [1:5696] Rails -- REDIS Payments mode is: false
2026-10-07 14:25:39.317612 I [1:5696] DemoEventsSubscriber -- Booting NATS API server...
2026-10-07 14:25:39.317689 I [1:5696] DemoEventsSubscriber -- Building 2 workers with options: {name: "demo-events-subscriber", version: "1.0.0"}, instance_args:
2026-10-07 14:25:39.317864 I [1:5696] DemoEventsSubscriber -- Setting up signal trap...
2026-10-07 14:25:39.333512 I [1:20368] DemoEventsSubscriber -- received {"page" => "/test12"}

With this change, when there's a typo with the subject and it doesn't belong to an existing stream:

Container prizepicks-devenv-rails-run-9aedc640d3b2 Creating
Container prizepicks-devenv-rails-run-9aedc640d3b2 Created
2026-10-07 14:26:16.847193 I [1:5696] Rails -- REDIS Audit mode is: false
2026-10-07 14:26:16.847226 I [1:5696] Rails -- REDIS Payments mode is: false
2026-10-07 14:26:25.304443 I [1:5696] DemoEventsSubscriber -- Booting NATS API server...
2026-10-07 14:26:25.305243 I [1:5696] DemoEventsSubscriber -- Building 2 workers with options: {name: "demo-events-subscriber", version: "1.0.0"}, instance_args:
2026-10-07 14:26:25.306158 I [1:5696] DemoEventsSubscriber -- Setting up signal trap...
2026-10-07 14:26:25.379892 E [1:worker-2 leopard_stream_patch.rb:13] DemoEventsSubscriber -- JetStream endpoint event_page_loaded failed to start:  -- Exception: Rubyists::Leopard::ConfigurationError: JetStream endpoint event_page_loaded has no stream and none captures subject event.page_loaded, create the stream or set `stream:`