feat: consume from NATS JetStream, and drop Pulsar

[bludot]

Same treatment as weeb-vip/anime-sync#22 and weeb-vip/character-staff-sync#8. Adds serve-image-sync-nats alongside serve-image-sync-kafka.

image_processor_kafka → image_processor

The _kafka suffix described the signature, not the logic: a grep for DriverMessage, RawData and Headers came back empty — it only reads Payload. So it takes the driver message as a type parameter and serves both transports:

image_processor.NewImageProcessor[*kafka.Message](store)   // kafka handler
image_processor.NewImageProcessor[*epNats.Message](store)  // nats handler

The old Pulsar-only image_processor package is deleted, which freed the accurate name.

No transform middleware — and that is correct

Unlike the CDC consumers, neither handler here has one. ep's processor hands the raw body to Event.Transform, and both drivers pass it identically:

handler(ctx, message, message.Data)   // nats driver
handler(ctx, message, msg.Value)      // kafka driver

So Payload is populated the same way on both. The CDC consumers need a transform only because their bodies carry a Debezium {schema, payload} envelope; image-sync messages are the sync services' own JSON.

NATSSTREAMNAME is empty here, on purpose

The CDC consumers bind to Debezium's ANIMEDBSTAGING stream. This one must not: image-sync is produced by the sync services, so nothing else declares a stream over it and the driver should create one from the subject. Naming Debezium's stream would graft image-sync onto a stream whose retention is sized for change events.

Pulsar removed

No Pulsar pods, no Pulsar ArgoCD apps. Checked before deleting this time — the only two pulsar mentions outside the handler were comments, not code, and image_backfill's comment describes historical data shape (two producers keyed characters differently over time), so it stays. The stale one in imagepath now says Kafka/NATS.

Note for review

internal/worker/pool.go shows a 14-line diff I did not author — gofmt -w fixed pre-existing misformatting (&Pool[T] { → &Pool[T]{, field alignment) in a file that was unformatted on main. Kept rather than reverted, since restoring badly-formatted code to keep a diff tidy is the wrong trade.

Verification

• go build, go vet, gofmt clean; go test ./... passes
• Docker image built as CI does; binary lists both commands:

serve-image-sync-kafka  serve-image-sync-nats

🤖 Generated with Claude Code

[bludot]

🎉 This PR is included in version 1.16.0 🎉

The release is available on:

• v1.16.0
• v1.16.0
• GitHub release

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