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>

packages/auth/src/di/bind-dev-seed.ts

@@ -6,7 +6,6 @@ import {
   type ILogger,
 } from "@repo/core-shared/instrumentation";
 import type { BindContext } from "@repo/core-shared/di";
-import type { IEventBus } from "@repo/core-events";
 import { authContainer } from "./container.js";
 import { AUTH_SYMBOLS } from "./symbols.js";
 import { MockUsersRepository } from "../infrastructure/repositories/users.repository.mock.js";
@@ -78,7 +77,7 @@ export async function bindDevSeedAuth(ctx: BindContext): Promise<void> {
     withCapture(
       logger,
       { feature: "auth", layer: "use-case", name: "auth.signUp" },
-      signUpUseCase(repo, authService, bus as IEventBus),
+      signUpUseCase(repo, authService, bus),
     ),
   );
   const wrappedSignOut = withSpan(

packages/auth/src/di/bind-production.ts

@@ -6,7 +6,6 @@ import {
   type ILogger,
 } from "@repo/core-shared/instrumentation";
 import type { BindProductionContext } from "@repo/core-shared/di";
-import type { IEventBus } from "@repo/core-events";
 import { authContainer } from "./container";
 import { AUTH_SYMBOLS } from "./symbols";
 import { UsersRepository } from "../infrastructure/repositories/users.repository";
@@ -69,7 +68,7 @@ export function bindProductionAuth(ctx: BindProductionContext): void {
     withCapture(
       logger,
       { feature: "auth", layer: "use-case", name: "auth.signUp" },
-      signUpUseCase(repo, authService, bus as IEventBus),
+      signUpUseCase(repo, authService, bus),
     ),
   );
   const wrappedSignOut = withSpan(