Refactor dashboard PubSub consumers to Stream.fromQueue pipelines

[danielbdyer]

Motivation

• Replace fragile manual Queue.take loops with Stream.fromQueue pipelines to centralize consumer behaviour and reduce imperative loop code.
• Provide a reusable consumer abstraction that supports event-kind filtering, batching/time-window semantics, and explicit error hooks so multiple subscribers share consistent flush/ordering guarantees.
• Preserve the Effect PubSub as the canonical event source while making downstream consumers (SAB writer, WS broadcaster, journal writer) composable via streams.

Description

• Added a reusable stream consumer module lib/infrastructure/dashboard/pubsub-stream-consumer.ts exposing subscribePubSubStreamConsumer with options for eventKinds, batching (groupedWithin), onEvent/onBatch sinks, and onError handling.
• Replaced manual Queue.take intake loops in lib/infrastructure/dashboard/pipeline-event-bus.ts with the new consumer for the SharedArrayBuffer + string channel writer and for the WS broadcaster.
• Refactored lib/infrastructure/dashboard/journal-writer.ts to consume events via the shared stream consumer using batched groupedWithin semantics and to perform batched enrich/append/index updates while preserving the original spaced flush cadence.
• Added law-style tests tests/dashboard-stream-consumer.laws.spec.ts that validate no event loss and FIFO ordering under burst load and that batching preserves spaced flush semantics.

Testing

• Ran the targeted test suite with npm run test -- tests/dashboard-stream-consumer.laws.spec.ts tests/pubsub-backpressure.laws.spec.ts tests/flywheel-server-integration.laws.spec.ts and all tests passed (22 passed).
• The new dashboard-stream-consumer tests exercised burst-load ordering and groupedWithin-based batching behavior and succeeded.
• Type checking via npm run typecheck surfaced unrelated missing generated module declarations (../generated/tesseract-knowledge / ../lib/generated/tesseract-knowledge) and failed; this is pre-existing and not caused by these changes.

---

Codex Task