fix: address Phase 1 spec review findings

- di-explainer.html: update stale JS data strings from positional-arg
  form (bindAllProduction(config), bindProductionBlog(config,tracer,...))
  to ctx-arg form (bindAllProduction(deps), bindProductionBlog(ctx)) with
  a note on ctx shape.
- auth/sign-up.use-case: change bus param from IEventBus to
  EventBusProtocol|undefined; guard bus.publish with if(bus) so the use
  case is safe when core-events is absent (Phase 3+).
- auth/bind-production + bind-dev-seed: drop as IEventBus cast and unused
  IEventBus import; ctx.bus is now passed directly (typed as
  EventBusProtocol|undefined).
- marketing-pages/bind-production + bind-dev-seed: drop as IJobQueue cast
  and unused IJobQueue import; wrap event-handler DI block in if(queue)
  guard so the handler is only bound when core-jobs is wired.
- core-shared/src/index.ts: add `export * from "./di"` as the plan
  specified (subpath export alone is no longer the only access path).

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

docs/architecture/di-explainer.html

@@ -1300,11 +1300,11 @@ const MODES = {
     ],
   },
   prod: {
-    flag: 'NODE_ENV="production", USE_DEV_SEED unset · bindAllProduction(config) ran',
+    flag: 'NODE_ENV="production", USE_DEV_SEED unset · bindAllProduction(deps) ran',
     scenarioTag: 'when this happens',
     title: 'Production binder ran at app boot',
     narrative: [
-      "App's bindAll() did not see USE_DEV_SEED=true, so it dispatched to bindAllProduction(). That resolved instrumentation (Rule 0), resolved a Payload-backed bus + queue (ADR-015), awaited the Payload config, and called bindProductionBlog(config, tracer, logger, bus, queue).",
+      "App's bindAll() did not see USE_DEV_SEED=true, so it dispatched to bindAllProduction(). That resolved instrumentation (Rule 0), resolved a Payload-backed bus + queue (ADR-015), awaited the Payload config, and called bindProductionBlog(ctx) where ctx carries { config, tracer, logger, bus?, queue?, realtime?, realtimeRegistry? }.",
       "The binder unbound IArticlesRepository and rebound it with .toConstantValue(new ArticlesRepository(config, tracer, logger)) — the real Payload-backed implementation that will hit Postgres on every method call.",
       "Use cases and controllers still resolve through their .toDynamicValue closures, but the closures now fetch the real repo. Callers cannot tell the difference — same interface, different storage."
     ],